Inhibitors of interleukin-1β converting enzyme

ABSTRACT

The present invention relates to novel classes of compounds which are inhibitors of interleukin-1β converting enzyme. The ICE inhibitors of this invention are characterized by specific structural and physicochemical features. This invention also relates to pharmaceutical compositions comprising these compounds. The compounds and pharmaceutical compositions of this invention are particularly well suited for inhibiting ICE activity and consequently, may be advantageously used as agents against interleukin-1 mediated diseases, including inflammatory diseases, autoimmune diseases and neurodegenerative diseases. This invention also relates to methods for inhibiting ICE activity and methods for treating interleukin-1 mediated diseases using the compounds and compositions of this invention.

CROSS REFERENCE TO PRIOR APPLICATION

This application is a continuation-in-part of co-pending U.S. application Ser. No. 08/261,452, filed Jun. 17, 1994.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to novel classes of compounds which are inhibitors of interleukin-1β converting enzyme ("ICE"). The ICE inhibitors of this invention are characterized by specific structural and physicochemical features. This invention also relates to pharmaceutical compositions comprising these compounds. The compounds and pharmaceutical compositions of this invention are particularly well suited for inhibiting ICE activity and consequently, may be advantageously used as agents against interleukin-1 ("IL-1") mediated diseases, including inflammatory diseases, autoimmune diseases and neurodegenerative diseases. This invention also relates to methods for inhibiting ICE activity and methods for treating interleukin-1 mediated diseases using the compounds and compositions of this invention.

BACKGROUND OF THE INVENTION

Interleukin 1 ("IL-1") is a major proinflammatory and immunoregulatory protein that stimulates fibroblast differentiation and proliferation, the production of prostaglandins, collagenase and phospholipase by synovial cells and chondrocytes, basophil and eosinophil degranulation and neutrophil activation. Oppenheim, J. H. et al, Immunology Today, 7, pp. 45-56 (1986). As such, it is involved in the pathogenesis of chronic and acute inflammatory and autoimmune diseases. IL-1 is predominantly produced by peripheral blood monocytes as part of the inflammatory response and exists in two distinct agonist forms, IL-1α and IL-1β. Mosely, B. S. et al., Proc. Nat. Acad. Sci., 84, pp. 4572-4576 (1987); Lonnemann, G. et al., Eur. J. Immunol., 19, pp. 1531-1536 (1989).

IL-1β is synthesized as a biologically inactive precursor, pIL-1β. pIL-1β lacks a conventional leader sequence and is not processed by a signal peptidase. March, C. J., Nature, 315, pp. 641-647 (1985). Instead, pIL-1β is cleaved by interleukin-1β converting enzyme ("ICE") between Asp-116 and Ala-117 to produce the biologically active C-terminal fragment found in human serum and synovial fluid. Sleath, P. R., et al., J. Biol. Chem., 265, pp. 14526-14528 (1992); A. D. Howard et al., J, Immumol., 147, pp. 2964-2969 (1991). Processing by ICE is also necessary for the transport of mature IL-1β through the cell membrane.

ICE is a cysteine protease localized primarily in monocytes. It converts precursor IL-1β to the mature form. Black, R. A. et al., FEBS Lett., 247, pp. 386-390 (1989); Kostura, M. J. et al., Proc, Natl, Acad. Sci. USA, 86, pp. 5227-5231 (1989). ICE, or its homologues, also appears to be involved in the regulation of cell death or apoptosis. Yuan, J. et al., Cell, 75, pp. 641-652 (1993); Miura, M. et al., Cell, 75, pp. 653-660 (1993); Nett-Fiordalisi, M. A. et al., J. Cell Biochem., 17B, p. 117 (1993). In particular, ICE or ICE homologues are thought to be associated with the regulation of apoptosis in neurogenerative diseases, such as Alzheimer's and Parkinson's disease. Marx, J. and M. Baringa, Science, 259, pp. 760-762 (1993); Gagliardini, V. et al., Science, 263, pp. 826-828 (1994).

ICE has been previously described as a heterodimer composed of two subunits, p20 and p10 (20kDa and 10kDa molecular weight, respectively). These subunits are derived from a 45kDa proenzyme (p45) by way of a p30 form, through an activation mechanism that is autocatalytic. Thornberry, N. A. et al., Nature, 356, pp. 768-774 (1992). The ICE proenzyme has been divided into several functional domains: a prodomain (p14), a p22/20 subunit, a polypeptide linker and a p10 subunit. Thornberry et al., supra; Casano et al., Genomics, 20, pp. 474-481 (1994).

Full length p45 has been characterized by its cDNA and amino acid sequences. PCT patent applications WO 91/15577 and WO 94/00154. The p20 and p10 cDNA and amino acid sequences are also known. Thornberry al., supra. Murine and rat ICE have also been sequenced and cloned. They have high amino acid and nucleic acid sequence homology to human ICE. Miller, D. K. et al., Ann. N.Y. Acad. Sci., 696, pp. 133-148 (1993); Molineaux, S. M. et al., Proc. Nat. Acad. Sci., 90, pp. 1809-1813 (1993). Knowledge of the primary structure of ICE, however, does not allow prediction of its tertiary structure. Nor does it afford an understanding of the structural, conformational and chemical interactions of ICE and its substrate pIL-1β or other substrates or inhibitors.

ICE inhibitors represent a class of compounds useful for the control of inflammation or apoptosis or both. Peptide and peptidyl inhibitors of ICE have been described. PCT patent applications WO 91/15577; WO 93/05071; WO 93/09135; WO 93/14777 and WO 93/16710; and European patent application 0 547 699. However, due to their peptidic nature, such inhibitors are typically characterized by undesirable pharmacologic properties, such as poor oral absorption, poor stability and rapid metabolism. Plattner, J. J. and D. W. Norbeck, in Drug Discovery Technologies, C. R. Clark and W. H. Moos, Eds. (Ellis Horwood, Chichester, England, 1990), pp. 92-126. This has hampered their development into effective drugs.

Accordingly, the need exists for compounds that can effectively inhibit the action of ICE, for use as agents for preventing and treating chronic and acute forms of IL-1 mediated diseases, including various cancers, as well as inflammatory, autoimmune or neurodegenerative diseases.

SUMMARY OF THE INVENTION

The present invention provides novel classes of compounds, and pharmaceutically acceptable derivatives thereof, that are useful as inhibitors of ICE. These compounds can be used alone or in combination with other therapeutic or prophylactic agents, such as antibiotics, immunomodulators or other anti-inflammatory agents, for the treatment or prophylaxis of diseases mediated by IL-1. According to a preferred embodiment, the compounds of this invention are capable of binding to the active site of ICE and inhibiting the activity of that enzyme.

It is a principal object of this invention to provide novel classes of inhibitors of ICE. These novel classes of ICE inhibitors are characterized by the following structural and physicochemical features:

a) a first and a second hydrogen bonding moiety, each of said moieties being capable of forming a hydrogen bond with a different backbone atom of ICE, said backbone atom being selected from the group consisting of the carbonyl oxygen of Arg-341, the amide --NH-- group of Arg-341, the carbonyl oxygen of Ser-339 and the amide --NH-- group of Ser-339;

b) a first and a second moderately hydrophobic moiety, said moieties each being capable of associating with a separate binding pocket of ICE when the inhibitor is bound thereto, said binding pocket being selected from the group consisting of the P2 binding pocket, the P3 binding pocket, the P4 binding pocket and the P' binding pocket; and

c) an electronegative moiety comprising one or more electronegative atoms, said atoms being attached to the same atom or to adjacent atoms in the moiety and said moiety being capable of forming one or more hydrogen bonds or salt bridges with residues in the P1 binding pocket of ICE.

It is also an object of this invention to provide a method for identification, design or prediction of ICE inhibitors comprising the steps of:

a) selecting a candidate compound of defined chemical structure comprising at least two hydrogen bonding moieties, at least two moderately hydrophobic moieties and one electronegative moiety comprising one or more electronegative atoms attached either to the same atom or to adjacent atoms in the electronegative moiety;

b) determining a low-energy conformation for binding of said compound to the active site of ICE;

c) evaluating the capability of said compound in said conformation to form at least two hydrogen bonds with the non-carbon backbone atoms of Arg-341 and Ser-339 of ICE;

d) evaluating the capability of said compound in said conformation to associate with at least two of the binding pockets of ICE selected from the group consisting of the P2 binding pocket, the P3 binding pocket, the P4 binding pocket and the P' binding pocket;

e) evaluating the capability of said compound in said conformation to interact with the P1 binding pocket of ICE; and

f) accepting or rejecting said candidate compound as an ICE inhibitor based on the determinations and evaluations carried out in the preceding steps.

It is a further object of this invention to provide novel classes of ICE inhibitors represented by formulas: ##STR1##

    ______________________________________                                         ABBREVIATIONS AND DEFINITIONS                                                                    Abbreviations                                                Designation       Reagent or Fragment                                          ______________________________________                                         Ala               alanine                                                      Arg               arginine                                                     Asn               asparagine                                                   Asp               aspartic acid                                                Cys               cysteine                                                     Gln               glutamine                                                    Glu               glutamic acid                                                Gly               glycine                                                      His               histidine                                                    Ile               isoleucine                                                   Leu               leucine                                                      Lys               lysine                                                       Met               methionine                                                   Phe               phenylalanine                                                Pro               proline                                                      Ser               serine                                                       Thr               threonine                                                    Trp               tryptophan                                                   Tyr               tyrosine                                                     Val               valine.                                                      ______________________________________                                    

Definitions

The following terms are employed herein:

The term "active site" refers to any or all of the following sites in ICE: the substrate binding site, the site where an inhibitor binds and the site where the cleavage of substrate occurs. The active site is characterized by at least amino acid residues: 173, 176, 177, 178, 179, 180, 236, 237, 238, 239, 244, 248, 283, 284, 285, 290, 338, 339, 340, 341, 342, 343, 344, 345, 348, 352, 381, 383, using the sequence and numbering according to Thornberry et al., supra.

The terms "P binding pocket", "S subsite", "S pocket", and the like, refer to binding subsites, or portions of the substrate binding site on the ICE molecule. The amino acid residues of the substrate are given designations according to their position relative to the scissile bond, i.e. the bond which is broken by the protease. The residues are designated P1, P2, etc., for those extending toward the N-terminus of the substrate and P1', P2', etc., for those extending toward the C-terminus of the substrate. The portions of an inhibitor which correspond to the P or P' residues of the substrate are also labeled P1, P1', etc., by analogy with the substrate. The binding subsites of the ICE molecule which receive the residues labeled P1, P1', etc., are designated S1, S1', etc., or may alternately be designated "the P1 binding pocket", "the P1' binding pocket", etc. [I. Schechter and A. Berger, "On the Size of the Active Site in Proteases", Biochem. Biophys. Res. Commun., vol. 27, pp. 157-162 (1967).]

The terms "P2 binding pocket" or "S2 subsite" of the ICE active site are equivalent and are defined as the space surrounded by amino acid residues Pro-290, Val-338 or Trp-340.

The terms "P3 binding pocket" or "S3 subsite" of the ICE active site are equivalent and are defined as the space surrounded by amino acid residues Pro-177, Arg-178, Thr-180, Arg-341 or Pro-343.

The terms "P4 binding pocket" or "S4 subsite" of the ICE active site are equivalent and are defined as the space surrounded by amino acid residues His-342, Met-345, Val-348, Arg-352, Asp-381, Arg-383 or Trp-340.

The terms "P1 binding pocket" or "S1 subsite" of the ICE active site are equivalent and are defined as the space surrounded by amino acid residues Arg-179, His-237, Gln-283, or Arg-341.

The terms "P' binding pocket" or "S' subsite" of the ICE active site are equivalent and are defined as the space surrounded by amino acid residues Phe-173, Ile-176, His-237, Gly-238, Ile-239, Cys-244 or His-248.

The term "hydrophobic" refers to a moiety which tends not to dissolve in water and is fat-soluble. Hydrophobic moieties include, but are not limited to, hydrocarbons, such as alkanes, alkenes, alkynes, cycloalkanes, cycloalkenes, cycloalkynes and aromatic compounds, such as aryls, certain saturated and unsaturated heterocycles and moieties that are substantially similar to the side chains of hydrophobic natural and unnatural α-amino acids, including valine, leucine, isoleucine, methionine, phenylanine, α-amino isobutyric acid, alloisoleucine, tyrosine, and tryptophan.

The term "moderately hydrophobic" refers to a hydrophobic moiety in which one or two carbon atoms have been replaced with more polar atoms, such as oxygen or nitrogen.

The term "heterocycle" or "heterocyclic" refers to a stable mono- or polycyclic compound which may optionally contain one or two double bonds or may optionally contain one or more aromatic rings. Each heterocycle consists of carbon atoms and from one to four heteroatoms independently selected from a group including nitrogen, oxygen, and sulfur. As used herein, the terms "nitrogen heteroatoms" and "sulphur heteroatoms" include any oxidized form of nitrogen or sulfur and the quaternized form of any basic nitrogen. Heterocycles defined above include, for example, pyrimidinyl, tetrahydroquinolyl, tetrahydroisoquinonlinyl, purinyl, pyrimidyl, indolinyl, benzimidazolyl, imidazolyl, imidazolinoyl, imidazolidinyl, quinolyl, isoquinolyl, indolyl, pyridyl, pyrrolyl, pyrrolinyl, pyrazolyl, pyrazinyl, quinoxolyl, piperidinyl, morpholinyl, thiamorpholinyl, furyl, thienyl, triazolyl, thiazolyl, β-carbolinyl, tetrazolyl, thiazolidinyl, benzofuranoyl, thiamorpholinyl sulfone, benzoxazolyl, oxopiperidinyl, oxopyrrol, dinyl, oxoazepinyl, azepinyl, isoxazolyl, tetrahydropyranyl, tetrahydrofuranyl, thiadiazolyl, benzodioxolyl, benzothienyl, tetrahydrothiophenyl and sulfolanyl. Further heterocycles are described in A. R. Katritzky and C. W. Rees, eds., Comprehensive Heterocyclic Chemistry: The Structure, Reactions, Synthesis and Use of Heterocyclic Compounds, Vol. 1-8, Pergamon Press, N.Y. (1984).

The term "cycloalkyl" refers to a mono- or polycyclic group which contains 3 to 15 carbons and may optionally contain one or two double bonds. Examples include cyclohexyl, adamantyl and norbornyl.

The term "aryl" refers to a mono- or polycyclic group which contains 6, 10, 12, or 14 carbons in which at least one ring is aromatic. Examples include phenyl, naphthyl and biphenyl.

The term "heteroaromatic" refers to a mono- or polycyclic group which contains 1 to 15 carbon atoms and from 1 to 4 heteroatoms, each of which is selected independently from a group including sulphur, nitrogen and oxygen, and which additionally contains from 1 to 3 five or six membered rings, at least one of which is aromatic.

The term "alpha-amino acid" (α-amino acid) refers to both the naturally occurring amino acids and other "non-protein" α-amino acids commonly utilized by those in the peptide chemistry arts when preparing synthetic analogues of naturally occurring peptides, including D and L forms. The naturally occurring amino acids are glycine, alanine, valine, leucine, isoleucine, serine, methionine, threonine, phenylalanine, tyrosine, tryptophan, cysteine, proline, histidine, aspartic acid, asparagine, glutamic acid, glutamine, γ-carboxyglutamic acid, arginine, ornithine and lysine. Examples of "non-protein" alpha-amino acids include hydroxylysine, homoserine, homotyrosine, homophenylalanine, citrulline, kynurenine, 4-aminophenylalanine, 3-(2-naphthyl)-alanine, 3-(1-naphthyl)alanine, methionine sulfone, t-butyl-alanine, t-butylglycine, 4-hydroxyphenylglycine, aminoalanine, phenylglycine, vinylalanine, propargyl-glycine, 1,2,4-triazolo-3-alanine, 4,4,4-trifluoro-threonine, thyronine, 6-hydroxytryptophan, 5-hydro-xytryptophan, 3-hydroxykynurenine, 3-aminotyrosine, trifuoromethylalanine, 2-thienylalanine, (2-(4-pyridyl)ethyl)cysteine, 3,4-dimethoxy-phenylalanine, 3-(2-thiazolyl)alanine, ibotenic acid, 1-amino-1-cyclopentanecarboxylic acid, 1-amino-1-cyclohexanecarboxylic acid, quisqualic acid, 3-trifuoromethylphenylalanine, 4-trifuoro-methylphenylalanine, cyclohexylalanine, cyclo-hexylglycine, thiohistidine, 3-methoxytyrosine, elastatinal, norleucine, norvaline, alloisoleucine, homoarginine, thioproline, dehydroproline, hydroxyproline, isonipectotic acid, homoproline, cyclohexylglycine, α-amino-n-butyric acid, cyclohexylalanine, aminophenylbutyric acid, phenylalanines substituted at the ortho, meta, or para position of the phenyl moiety with one or two of the following: a (C₁ -C₄) alkyl, a (C₁ -C₄) alkoxy, halogen or nitro groups or substituted with a methylenedioxy group; β-2- and 3-thienylalanine, β-2- and 3-furanylalanine, β2-, 3- and 4-pyridylalanine, β-(benzothienyl-2- and 3-yl)alanine, β-(1- and 2-naphthyl)alanine, O-alkylated derivatives of serine, threonine or tyrosine, S-alkylated cysteine, S-alkylated homocysteine, O-sulfate, O-phosphate and O-carboxylate esters of tyrosine, 3-sulfo-tyrosine, 3-carboxy-tyrosine, 3-phospho-tyrosine, 4-methane sulfonic acid ester of tyrosine, 4-methane phosphonic acid ester of tyrosine, 3,5-diiodotyrosine, 3-nitrotyrosine, ε-alkyl lysine, and delta-alkyl ornithine. Any of these α-amino acids may be substituted with a methyl group at the alpha position, a halogen at any aromatic residue on the α-amino side chain, or an appropriate protective group at the O, N, or S atoms of the side chain residues. Appropriate protective groups are disclosed in "Protective Groups In Organic Synthesis," T. W. Greene and P. G. M. Wuts, J. Wiley & Sons, N.Y., N.Y., 1991.

The term "α-amino acid side chain residue" refers to a chemical moiety which is attached to the α-carbon of an alpha-amino acid.

The term "bioisosteric replacement for --CO₂ H" refers to group which may substitute for a carboxylic acid group in bioactive molecules. Examples of such groups are disclosed in Christopher A. Lipinski, "Bioisosteres in Drug Design" Annual Reports In Medical Chemistry, 21, pp. 286-88 (1986), and in C. W. Thornber, "Isosterism and Molecular Modification in Drug Design" Chemical Society Reviews, pp. 563-580 (1979).

The term "association" is used in reference to a condition of proximity between an inhibitor or portions thereof to an ICE molecule or portions thereof wherein the juxtaposition is energetically favored by electrostatic or van der Waals interactions.

The term "hydrogen bond" refers to a favorable interaction that occurs whenever a suitable donor atom, X, bearing a proton, H, and a suitable acceptor atom, Y, have a separation of between 2.5 Å and 3.5 Å and where the angle X--H - - - Y is greater than 90 degrees. Suitable donor and acceptor atoms are well understood in medicinal chemistry (G. C. Pimentel and A. L. McClellan, The Hydrogen Bond, Freeman, San Francisco, 1960; R. Taylor and O. Kennard, "Hydrogen Bond Geometry in Organic Crystals", Accounts of Chemical Research, 17, pp. 320-326 (1984)).

The term "salt bridge" refers to the non-covalent attractive interaction between a positively 10 Charged moiety (P) and a negatively charged moiety (N) when the distance between the centers of mass of P and N is between 2 and 6 Angstroms. In calculating the center of mass, atoms which may contain a formal charge and atoms immediately adjacent to these are included. For example, a salt bridge may be formed between the positively charged guanidinium side chain of an arginine residue and the negative charged carboxylate side chain of a glutamate residue. Salt bridges are well understood in medicinal chemistry (L. Stryer, Biochemistry, Freeman, San Francisco, (1975); K. A. Dill, "Dominant Forces in Protein Folding", Biochemistry, 29, No. 31, pp. 7133-7155, (1990)).

The term "center of mass" refers to a point in three-dimensional space which represents a weighted average position of the masses that make up an object.

The terms "backbone chain" and "backbone" refer to the portion of a polypeptide which comprises the repeating unit --CO--CH--NH--.

The term "scaffold" refers to a structural building block which forms the basis of an ICE inhibitor according to this invention. Various moieties and functional groups are intended to be appended to the scaffold. The scaffolds of this invention are thus depicted having open valences. Various scaffolds of ICE inhibitors according to this invention include the portions: ##STR2## In those scaffolds, the NH and CO or SO₂ moieties represent a first and a second hydrogen bonding moiety, said moieties each being capable of forming a hydrogen bond with a backbone atom of ICE, said backbone atom being selected from the group consisting of the carbonyl oxygen of Arg-341, the amide --NH-- of Arg-341, the carbonyl oxygen of Ser-339 and the amide --NH-- of Ser-339.

The term "substitute" refers to the replacement of a hydrogen atom in a compound with a substituent group. In the present invention, those hydrogen atoms which form a part of a hydrogen bonding moiety which is capable of forming a hydrogen bond with the carbonyl oxygen of Arg-341 of ICE or the carbonyl oxygen of Ser-339 of ICE are excluded from substitution. These excluded hydrogen atoms include those which comprise an --NH-- group which is alpha to a Z or a --CO-- group and are depicted as --NH-- rather than an X group or some other designation in the following diagrams: (a) through (t), (v), (rr) through (uu), (xx) through (zz), (aaa) through (ggg), and (I) through (VIID).

The term "straight chain" refers to a contiguous unbranching string of covalently bound members, i.e. atoms, which form a portion of a ring. The straight chain and the ring of which it forms a part may be substituted, but these substituents are not a part of the straight chain.

The term "K_(i) " refers to a numerical measure of the effectiveness of a compound in inhibiting the activity of a target enzyme such as ICE. Lower values of K_(i) reflect higher effectiveness. The K_(i) value is a derived by fitting experimentally determined rate data to standard enzyme kinetic equations (see I. H. Segel, Enzyme Kinetics, Wiley-Interscience, 1975).

The term "minimize" refers to the systematic altering of the atomic geometry of a molecule or molecular complex so that any further minor perturbation of the atomic geometry would cause the total energy of the system as measured by a molecular mechanics force-field to increase. Minimization and molecular mechanics force-fields are well understood in computational chemistry [U. Burkert and N. L. Allinger, Molecular Mechanics, ACS Monograph 177, American Chemical Society, Washington, D.C. 1982 pages 59-78].

The term "strain energy" is used in this application to refer to the difference between the free conformation energy of a compound and the bound conformation energy of that compound when bound to ICE. The strain energy can be determined by the following steps: Evaluate the energy of the molecule when it has the conformation necessary for binding to ICE. Then minimize and reevaluate the energy--this is the free conformation energy. The strain energy for binding of a potential inhibitor to ICE is the difference between the free conformation energy and the bound conformation energy. In a preferred embodiment, the strain energy of an inhibitor of the present invention is less than about 10 kcal/mol.

The term "patient" as used in this application refers to any mammal, especially humans.

The term "pharmaceutically effective amount" refers to an amount effective in treating or ameliorating an IL-1 mediated disease in a patient. The term "prophylactically effective amount" refers to an amount effective in preventing or substantially lessening IL-1 mediated disease in a patient.

The term "pharmaceutically acceptable carrier or adjuvant" refers to a non-toxic carrier or adjuvant that may be administered to a patient, together with a compound of this invention, and which does not destroy the pharmacological activity thereof.

The term "pharmaceutically acceptable derivative" means any pharmaceutically acceptable salt, ester, or salt of such ester, of a compound of this invention or any other compound which, upon administration to a recipient, is capable of providing (directly or indirectly) a compound of this invention or an anti-ICE active metabolite or residue thereof.

Pharmaceutically acceptable salts of the compounds of this invention include, for example, those derived from pharmaceutically acceptable inorganic and organic acids and bases. Examples of suitable acids include hydrochloric, hydrobromic, sulfuric, nitric, perchloric, fumaric, maleic, phosphoric, glycolic, lactic, salicylic, succinic, toluene-p-sulfonic, tartaric, acetic, citric, methanesulfonic, formic, benzoic, malonic, naphthalene-2-sulfonic and benzenesulfonic acids. Other acids, such as oxalic, while not in themselves pharmaceutically acceptable, may be employed in the preparation of salts useful as intermediates in obtaining the compounds of the invention and their pharmaceutically acceptable acid addition salts. Salts derived from appropriate bases include alkali metal (e.g., sodium), alkaline earth metal (e.g., magnesium), ammonium and N-(C₁₋₄ alkyl)₄ ⁺ salts.

This invention also envisions the "quaternization" of any basic nitrogen-containing groups of the compounds disclosed herein. The basic nitrogen can be quaternized with any agents known to those of ordinary skill in the art including, for example, lower alkyl halides, such as methyl, ethyl, propyl and butyl chloride, bromides and iodides; dialkyl sulfates including dimethyl, diethyl, dibutyl and diamyl sulfates; long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides; and aralkyl halides including benzyl and phenethyl bromides. Water or oil-soluble or dispersible products may be Obtained by such quaternization.

The ICE inhibitors of this invention may contain one or more "asymmetric" carbon atoms and thus may occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. All such isomeric forms of these compounds are expressly included in the present invention. Each stereogenic carbon may be of the R or S configuration. Although specific compounds and scaffolds exemplified in this application may be depicted in a particular stereochemical configuration, compounds and scaffolds having either the opposite stereochemistry at any given chiral center or mixtures. thereof are also envisioned.

The ICE inhibitors of this invention may comprise ring structures which may optionally be substituted at carbon, nitrogen or other atoms by various substituents. Such ring structures may be singly or multiply substituted. Preferably, the ring structures contain between 0 and 3 substituents. When multiply substituted, each substituent may be picked independently of any other substituent as long as the combination of substituents results in the formation of a stable compound.

Combinations of substituents and variables envisioned by this invention are only those that result in the formation of stable compounds. The term "stable", as used herein, refers to compounds which possess stability sufficient to allow manufacture and administration to a mammal by methods known in the art. Typically, such compounds are stable at a temperature of 40° C. or less, in the absence of moisture or other chemically reactive conditions, for at least a week.

DETAILED DESCRIPTION OF THE INVENTION

In order that the invention herein described may be more fully understood, the following detailed description is set forth.

We have discovered that compounds possessing the following novel combination of features are surprisingly effective ICE inhibitors:

a) a first and a second hydrogen bonding moiety, each of said moieties being capable of forming a hydrogen bond with a different backbone atom of ICE, said backbone atom being selected from the group consisting of the carbonyl oxygen of Arg-341, the amide --NH-- group of Arg-341, the carbonyl oxygen of Ser-339 and the amide --NH-- group of Ser-339;

b) a first and a second moderately hydrophobic moiety, said moieties each being capable of associating with a separate binding pocket of ICE when the inhibitor is bound thereto, said binding pocket being selected from the group consisting of the P2 binding pocket, the P3 binding pocket, the P4 binding pocket and the P' binding pocket; and

c) an electronegative moiety comprising one or more electronegative atoms, said atoms being attached to the same atom or to adjacent atoms in the moiety and said moiety being capable of forming one or more hydrogen bonds or salt bridges with residues in the P1 binding pocket of ICE.

Preferably, any moderately hydrophobic moiety associating with the P2 binding pocket of ICE does so in such a way that:

a) the distance from the center of mass of the moderately hydrophobic moiety in the P2 binding pocket to the carbonyl oxygen of Arg-341 of ICE is between about 7.1 Å and about 12.5 Å;

b) the distance from the center of mass of the moderately hydrophobic moiety in the P2 binding pocket to the amide nitrogen of Arg-341 of ICE is between about 6.0 Å and about 12 Å; and

c) the distance from the center of mass of the moderately hydrophobic moiety in the P2 binding pocket to the carbonyl oxygen of Ser-339 of ICE is between about 3.7 Å and about 9.5 Å.

Preferably, any moderately hydrophobic moiety associating with the P3 binding pocket of ICE does so in such a way that:

a) the distance from the center of mass of the moderately hydrophobic moiety in the P3 binding pocket to the carbonyl oxygen of Arg-341 of ICE is between about 3.9 Å and about 9.5 Å;

b) the distance from the center of mass of the moderately hydrophobic moiety in the P3 binding pocket to the amide nitrogen of Arg-341 of ICE is between about 5.4 Å and about 11 Å; and

c) the distance from the center of mass of the moderately hydrophobic moiety in the P3 binding pocket to the carbonyl oxygen of Ser-339 of ICE is between about 7.0 Å and about 13 Å.

Preferably, any moderately hydrophobic moiety associating with the P4 binding pocket of ICE does so in such a way that:

a) the distance from the center of mass of the moderately hydrophobic moiety in the P4 binding pocket to the carbonyl oxygen of Arg-341 of ICE is between about 4.5 Å and about 7.5 Å;

b) the distance from the center of mass of the moderately hydrophobic moiety in the P4 binding pocket to the amide nitrogen of Arg-341 of ICE is between about 5.5 Å and about 8.5 Å; and

c) the distance from the center of mass of the moderately hydrophobic moiety in the P4 binding pocket to the carbonyl oxygen of Ser-339 of ICE is between about 8 Å and about 11 Å.

Preferably, any moderately hydrophobic moiety associating with the P' binding pocket of ICE does so in such a way that:

a) the distance from the center of mass of the moderately hydrophobic moiety in the P' binding pocket to the carbonyl oxygen of Arg-341 of ICE is between about 11 Å and about 16 Å;

b) the distance from the center of mass of the moderately hydrophobic moiety in the P' binding pocket to the amide nitrogen of Arg-341 of ICE is between about 10 Å and about 15 Å; and

c) the distance from the center of mass of the moderately hydrophobic moiety in the P' binding pocket to the carbonyl oxygen of Ser-339 of ICE is between about 8 Å and about 12 Å.

More preferably, all of the above associative conditions are met in the compounds of this invention.

The practitioner skilled in the art will appreciate that there are a number of means to design the inhibitors of the present invention. These same means may be used to select a candidate compound for screening as an ICE inhibitor. This design or selection may begin with selection of the various moieties which fill binding pockets.

There are a number of ways to select moieties to fill individual binding pockets. These include visual inspection of a physical model or computer model of the active site and manual docking of models of selected moieties into various binding pockets. Modeling software that is well known and available in the art may be used. These include QUANTA [Molecular Simulations, Inc., Burlington, Mass., 1992], SYBYL [Molecular Modeling Software, Tripos Associates, Inc., St. Louis, Mo., 1992], AMBER [S. J. Weiner, P. A. Kollman, D. A. Case, U. C. Singh, C. Ghio, G. Alagona, and P. Weiner, J. Am. Chem, Soc., vol. 106, pp. 765-784 (1984)], or CHARMM [B. R. Brooks, R. E. Bruccoleri, B. D. Olafson, D. J. States, S. Swaminathan, and M. Karplus, J. Comp. Chem. vol. 4, pp. 187-217 (1983)]. This modelling step may be followed by energy minimization with standard molecular mechanics forcefields such as CHARMM and AMBER. In addition, there are a number of more specialized computer programs to assist in the process of selecting the binding moieties of this invention. These include:

1. GRID (Goodford, P. J. A Computational Procedure for Determining Energetically Favorable Binding Sites on Biologically Important Macromolecules. J. Med. Chem., 28, pp. 849-857 (1985)). GRID is available from Oxford University, Oxford, UK.

2. MCSS (Miranker, A.; Karplus, M. Functionality Maps of Binding Sites: A Multiple Copy Simultaneous Search Method. Proteins: Structure. Function and Genetics, 11, pp. 29-34 (1991)). MCSS is available from Molecular Simulations, Burlington, Mass.

3. AUTODOCK (Goodsell, D. S.; Olsen, A. J. Automated Docking of Substrates to Proteins by Simmulated Annealing. PROTEINS: Structure, Function and Genetics, 8, pp. 195-202 (1990)). AUTODOCK is available from the Scripps Research Institute, La Jolla, Calif.

4. DOCK (Kuntz, I. D.; Blaney, J. M.; Oatley, S. J.; Langridge, R.; Ferrin, T. E. A Geometric Approach to Macromolecule-Ligand interactions. J. Mol. Biol., 161, pp. 269-288 (1982)). DOCK is available from the University of California, San Francisco, Calif.

Once suitable binding moieties have been selected, they can be assembled into a single inhibitor. This assembly may be accomplished by connecting the various moieties to a central scaffold. The assembly process may, for example, be done by visual inspection followed by manual model building, again using software such as Quanta or Sybyl. A number of other programs may also be used to help select ways to connect the various moieties. These include:

1. CAVEAT (Bartlett, P. A.; Shea, G. T.; Telfer, S. J.; Waterman, S. CAVEAT: A Program to Facilitate the Structure-Derived Design of Biologically Active Molecules. In "Molecular Recognition in Chemical and Biological Problems," Special Pub., Royal Chem. Soc., 78, pp. 182-196 (1989)). CAVEAT is available from the University of California, Berkeley, Calif.

2. 3D Database systems such as MACCS-3D (MDL Information Systems, San Leandro, Calif.). This area has been recently reviewed by Martin (Martin, Y. C. 3D Database Searching in Drug Design. J. Med. Chem., 35, pp. 2145-2154 (1992)).

3. HOOK (available from Molecular Simulations, Burlington, Mass.).

In addition to the above computer assisted modeling of inhibitor compounds, the inhibitors of this invention may be constructed "de novo" using either an empty active site or optionally including some portions of a known inhibitor. Such methods are well known in the art. They include, for example:

1. LUDI (Bohm, H. J. The Computer Program LUDI: A New Method for the be Novo Design of Enzyme Inhibitors. J. Comp. Aid. Molec. Design., 6, 61-78 (1992)). LUDI is available from Biosym Technologies, San Diego, Calif.

2. LEGEND (Nishibata, Y., Itai, A., Tetrahedron, 47, 8985 (1991)). LEGEND is available from Molecular Simultations, Burlington, Mass.

3. LeapFrog (available from Tripos associates, St. Louis, Mo.).

A number of techniques commonly used for modeling drugs may be employed (For a review, see: Cohen, N. C.; Blaney, J. M.; Humblet, C.; Gund, P.; Barry, D. C., "Molecular Modeling Software and Methods for Medicinal Chemistry", J. Med. Chem., 33, pp. 883-894 (1990)). There are likewise a number of examples in the chemical literature of techniques that can be applied to specific drug design projects. For a review, see: Navia, M. A. and Murcko, M. A., "The Use of Structural Information in Drug Design", Current Opinions in Structural Biology, 2, pp. 202-210 (1992). Some examples of these specific applications include: Baldwin, J. J. et al., "Thienothiopyran-2-sulfonamides: Novel Topically Active Carbonic Anhydrase Inhibitors for the Treatment of Glaucoma", J. Med. Chem., 32, pp. 2510-2513 (1989); Appelt, K. et al., "Design of Enzyme Inhibitors Using Iterative Protein Crystallographic Analysis", J. Med. Chem., 34, pp. 1925-1934 (1991); and Ealick, S. E. et al., "Application of Crystallographic and Modeling Methods in the Design of Purine Nucleotide Phosphorylase Inhibitors" Proc. Nat. Acad. Sci. USA, 88, pp. 11540-11544 (1991).

Using the novel combination of steps of the present invention, the skilled artisan can advantageously avoid time consuming and expensive experimentation to determine enzymatic inhibition activity of particular compounds. The method also is useful to facilitate rational design of ICE inhibitors and therapeutic and prophylactic agents against IL-1-mediated diseases. Accordingly, the present invention relates to such inhibitors.

A variety of conventional techniques may be used to carry out each of the above evaluations as well as the evaluations necessary in screening a candidate compound for ICE inhibiting activity. Generally, these techniques involve determining the location and binding proximity of a given moiety, the occupied space of a bound inhibitor, the deformation energy of binding of a given compound and electrostatic interaction energies. Examples of conventional techniques useful in the above evaluations include: quantum mechanics, molecular mechanics, molecular dynamics, Monte Carlo sampling, systematic searches and distance geometry methods (G. R. Marshall, Ann. Ref. Pharmacol. Toxicol., 27, p. 193 (1987)). Specific computer software has been developed for use in carrying out these methods. Examples of programs designed for such uses include: Gaussian 92, revision E.2 (M. J. Frisch, Gaussian, Inc., Pittsburgh, Pa. ©1993); AMBER, version 4.0 (P. A. Kollman, University of California at San Francisco, ©1993); QUANTA/CHARMM [Molecular Simulations, Inc., Burlington, Mass. ©1992]; and Insight II/Discover (Biosysm Technologies Inc., San Diego, Calif. ©1992). These programs may be implemented, for instance, using a Silicon Graphics Indigo 2 workstation or IBM RISC/6000 workstation model 550. Other hardware systems and software packages will be known and of evident applicability to those skilled in the art.

Different classes of active ICE inhibitors, according to this invention, may interact in similar ways with the various binding pockets of the ICE active site. The spatial arrangement of these important groups is often referred to as a pharmacophore. The concept of the pharmacophore has been well described in the literature (D. Mayer, C. B. Naylor, I. Motoc, and G. R. Marshall, J. Comp. Aided Molec. Design vol. 1, pp. 3-16 (1987); A. Hopfinger and B. J. Burke, in Concepts and Applications of Molecular Similarity, M. A. Johnson and G. M. Maggiora, ed., Wiley (1990)).

Different classes of ICE inhibitors of this invention may also use different scaffolds or core structures, but all of these cores will allow the necessary moieties to be placed in the active site such that the specific interactions necessary for binding may be obtained. These compounds are best defined in terms of their ability to match the pharmacophore, i.e., their structural identify relative to the shape and properties of the active site of ICE.

The ICE inhibitors of one embodiment of this invention comprise a first and a second hydrogen bonding moiety, a first and a second moderately hydrophobic moiety, and an electronegative moiety which comprise or are covalently bound to one of the following scaffolds: ##STR3##

The ICE inhibitors of another embodiment (A) of this invention are those of formulas: ##STR4## wherein: X; is CH or N;

g is 0 or 1;

each J is independently selected from the group consisting of --H, --OH, and --F, provided that when a first and second J are bound to a C and said first J is --OH, said second J is --H;

m is 0, 1, or 2;

T is --Ar₃, --OH, --CF₃, --CO--CO₂ H, --CO₂ H or any bioisosteric replacement for --CO₂ H;

R₁ is selected from the group consisting of the following formulae, in which any ring may optionally be singly or multiply substituted at any carbon by Q₁, at any nitrogen by R₅, or at any atom by ═O, --OH, --CO₂ H, or halogen, and in which any saturated ring may optionally be unsaturated at one or two bonds: ##STR5##

wherein each ring C is independently chosen from the group consisting of benzo, pyrido, thieno, pyrrolo, furano, thiazolo, isothiazolo, oxazolo, isoxazolo, pyrimido, imidazolo, cyclopentyl, and cyclohexyl;

R₃ is --CN, --CH═CH--R₉, --CH═N--O--R₉, --(CH₂)₁₋₃ --T₁ --R₉, --CJ₂ --R₉, --CO--R₁₃, or ##STR6## each R₄ is independently selected from the group consisting of: --H, --Ar₁, --R₉, --T₁ --R₉, and --(CH₂)₁,2,3 --T₁ --R₉,

each T₁ is independently selected from the group consisting of: --CH═CH--, --O--, --S--, --SO--, --SO₂ --, --NR₁₀ --, --NR₁₀ --CO--, --CO--, --O--CO--, --CO--O--, --CO--NR₁₀ --, --O--CO--NR₁₀ --, --NR₁₀ --CO--O--, --NR₁₀ CO--NR₁₀ --, --SO--NR₁₀ --, --NR₁₀ --SO₂ --, and --NR₁₀ --SO₂ --, --NR₁₀ --SO₂ --NR₁₀ --,

each R₅ is independently selected from the group consisting of: --H, --Ar₁, --CO--Ar₃, --SO₂ --Ar₁, --R₉, --CO--R₉, --CO--O--R₉, --SO₂ --R₉, ##STR7##

R₆ and R₇ taken together form a saturated 4-8 member carbocyclic ring or heterocyclic ring containing --O--, --S--, or --NH--, or

R₇ is --H and R₆ is --H, --Ar₁, --R₉, or --(CH₂)₁,2,3 --T₁ --R₉ ;

each R₉ is a C₁₋₆ straight or branched alkyl group optionally singly or multiply substituted by --OH, --F, or ═O and optionally substituted with one or two Ar₁ groups;

each R₁₀ is independently selected from the group consisting of --H or a C₁₋₆ straight or branched alkyl group;

each R₁₃ is independently selected from the group consisting of --Ar₂ and --R₄ ;

each Ar₁ is a cyclic group independently selected from the set consisting of an aryl group which contains 6, 10, 12, or 14 carbon atoms and between 1 and 3 rings, a cycloalkyl group which contains between 3 and 15 carbon atoms and between 1 and 3 rings, said cycloalkyl group being optionally benzofused, and a heterocycle group containing between 5 and 15 ring atoms and between 1 and 3 rings, said heterocycle group containing at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, said heterocycle group optionally containing one or more double bonds, said heterocycle group optionally comprising one or more aromatic rings, and said cyclic group optionally being singly or multiply substituted by ═O, --OH, perfluoro C₁₋₃ alkyl, or --Q₁ ;

each Ar₂ is independently selected from the following group, in which any ring may optionally be substituted by --Q₁ : ##STR8##

Ar₃ is a cyclic group selected from the set consisting of a phenyl ring, a 5-membered heteroaromatic ring, and a 6-membered heteroaromatic ring, said heteroaromatic rings comprising 1-3 heteroatom groups selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, said cyclic group optionally being singly or multiply substituted with ═O, --OH, halogen, perfluoro C₁₋₃ alkyl, or --CO₂ H;

each Q₁ is independently selected from the group consisting of: --Ar₁, --R₉, --T₁ --R₉, and --(CH₂)₁,2,3 --T₁ --R₉,

provided that when --Ar₁ is substituted with a Q₁ group which comprises one or more additional --Ar₁ groups, said additional --Ar₁ groups are not substituted with Q₁ ;

each X is independently selected from the group consisting of ═N--, and ═CH--;

each X₂ is independently selected from the group consisting of --O--, --CH₂ --, --NH--, --S--, --SO--, and --SO₂ ; each X₃ is independently selected from the group consisting of --CH₂ --, --S--, --SO--, and --SO₂ --;

each X₄ is independently selected from the group consisting of --CH₂ -- and --NH--;

each X₅ is independently selected from the group consisting of ##STR9##

X₆ is CH or N, provided that when X₆ is N in the R₁ group labeled (o) and X₅ is CH and X₂ is CH₂ the ring of the R₁ group labeled (o) must be substituted by Q₁ or benzofused;

each Y is independently selected from the group consisting of --O-- and --S--;

each Z is independently CO or SO₂,

each a is independently 0 or 1,

each c is independently 1 or 2,

each d is independently 0, 1, or 2,

each e is independently 0, 1, 2, or 3,

either R₃₁ is --H or --R₉ and R₃₂ is ##STR10## or R₃₁ is --H and R₃₂ is ##STR11##

R₃₀ is selected from the group consisting of the following formulae, in which any ring may optionally be singly or multiply substituted by ═O, --OH, --CO₂ H, --Q₁, or halogen and in which any saturated ring may optionally be unsaturated at one or two bonds: ##STR12##

A₁ is a direct bond, an alpha-amino acid, or beta-alanine;

A₂ is a direct bond, an alpha-amino acid, or beta-alanine;

T₅ is --(CJ₂)_(m) --T,

Y₄ is --O--, --S--, --CH═CH--, or --NH--,

X₇ is --NH-- or --CH₂ --,

R₁₆ is selected from the group consisting of the following formulae, in which any ring may optionally be singly or multiply substituted at any carbon by Q₁, at any nitrogen by R₅, or at any atom by ═O, --OH, --CO₂ H, or halogen, and in which any saturated ring may optionally be unsaturated at one or two bonds: ##STR13##

Z₁ is optionally C═O, S═O, or C═S.

The ICE inhibitors of another embodiment (B) of this invention are those of formula α: ##STR14## wherein:

X₁ is --CH;

g is 0 or 1;

each J is independently selected from the group consisting of --H, --OH, and --F, provided that when a first and second J are bound to a C and said first J is --OH, said second J is --H;

m is 0, 1, or 2;

T is --OH, --CO--CO₂ H, --CO₂ H or any bioisosteric replacement for --CO₂ H;

R₁ is selected from the group consisting of the following formulae, in which any ring may optionally be singly or multiply substituted at any carbon by Q₁, at any nitrogen by R₅, or at any atom by ═O, --OH, --CO₂ H, or halogen, any saturated ring may optionally be unsaturated at one or two bonds; and wherein R₁ (e) and R₁ (y) are optionally benzofused; ##STR15##

R₂₀ is selected from the group consisting of: ##STR16##

wherein each ring C is independently chosen from the group consisting of benzo, pyrido, thieno, pyrrolo, furano, thiazolo, isothiazolo, oxazolo, isoxazolo, pyrimido, imidazolo, cyclopentyl, and cyclohexyl;

R₃ is --CN, --CH═CH--R₉, --CN═N--O--R₉, --(CH₂)₁₋₃ --T₁ --R₉, --CJ₂ --R₉, --CO--R₁₃, or ##STR17##

each R₄ is independently selected from the group consisting of: --H, --Ar₁, --R₉, --T₁ --R₉, and --(CH₂)₁,2,3 --T₁ --R₉,

each T₁ is independently selected from the group consisting of: --CH═CH--, --O--, --S--, --SO₂ --, --NR₁₀ --, --NR₁₀ --CO--, --CO--, --O--CO--, --CO--O--, --CO--NR₁₀ --, --O--CO--NR₁₀ --, --NR₁₀ --CO--O--, --NR₁₀ --CO--NR₁₀ --, --SO₂ --NR₁₀ --, --NR₁₀ --SO₂ --, and --NR₁₀ --SO₂ --NR₁₀ --,

each R₅ is independently selected from the group consisting of: --H, --Ar₁, --CO--Ar₁, --SO₂ --Ar₁, --CO--NH₂, --SO₂ --NH₂, --R₉, --CO--R₉, --CO--O--R₉, --SO₂ --R₉, ##STR18##

R₆ and R₇ taken together form a saturated 4-8 member carbocyclic ring or heterocyclic ring containing --O--, --S--, or --NH--; or R₇ is --H and R₆ is: --H, --Ar₁, --R₉, (CH₂)₁,2,3 --T₁ --R₉, or an α-amino acid side chain residue;

each R₉ is a C₁₋₆ straight or branched alkyl group optionally singly or multiply substituted by --OH, --F, or ═O and optionally substituted with one or two Ar₁ groups;

each R₁₀ is independently selected from the group consisting of --H or a C₁₋₆ straight or branched alkyl group;

each R₁₃ is independently selected from the group consisting of --Ar₂, --R₄ and ##STR19##

each Ar₁ is a cyclic group independently selected from the set consisting of an aryl group which contains 6, 10, 12, or 14 carbon atoms and between 1 and 3 rings, a cycloalkyl group which contains between 3 and 15 carbon atoms and between 1 and 3 rings, said cycloalkyl group being optionally benzofused, and a heterocycle group containing between 5 and 15 ring atoms and between 1 and 3 rings, said heterocycle group containing at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, said heterocycle group optionally containing one or more double bonds, said heterocycle group optionally comprising one or more aromatic rings, and said cyclic group optionally being singly or multiply substituted by --NH₂, --CO₂ H, --Cl, --F, --Br, --I, --NO₂, --CN, ═O, --OH, -perfluoro C₁₋₃ alkyl, ##STR20## or --Q₁ ;

each Ar₂ is independently selected from the following group, in which any ring may optionally be singly or multiply substituted by --Q₁ and --Q₂ : ##STR21##

each Q₁ is independently selected from the group consisting of --Ar₁ --O--Ar₁ --R₉, --T₁ --R₉, and --(CH₂)₁,2,3 --T₁ --R₉ ;

each Q₂ is independently selected from the group consisting of --OH, --NH₂, --CO₂ H, --Cl, --F, --Br, --I, --NO₂, --CN, --CF₃, and ##STR22##

provided that when --Ar₁ is substituted with a Q₁ group which comprises one or more additional --Ar₁ groups, said additional --Ar₁ groups are not substituted with Q₁ ;

each X is independently selected from the group consisting of ═N--, and ═CH--;

each X₂ is independently selected from the group consisting of --O--, -CH₂ --, --NH--, --S--, --SO--, and --SO₂ --;

each X₃ is independently selected from the group consisting of --CH₂ --, --S--, --SO--, and --SO₂ --;

each X₄ is independently selected from the group consisting of --CH₂ -- and --NH--;

each X₅ is independently selected from the group consisting of ##STR23##

X₆ is CH or N, provided that when X₆ is N in the R₁ group labeled (o) and X₅ is CH and X₂ is CH₂ the ring of the R₁ group labeled (o) must be substituted by Q₁ or benzofused;

each Y is independently selected from the group consisting of --O-- and --S--, and --NH;

each Z is independently CO or SO₂,

each a is independently 0 or 1,

each c is independently 1 or 2,

each d is independently 0, 1, or 2, and

each e is independently 0, 1, 2, or 3;

provided that when

R₁ is (f),

R₆ is an α-amino acid side chain residue, and

R₇ is --H,

then (aa1) and (aa2) must be substituted with Q₁ ; also provided that when

R₁ is (o),

g is 0,

J is --H,

m is 1,

R₆ is an α-amino acid side chain residue,

R₇ is

X₂ is --CH₂ --, ##STR24## or --CO--R₁₃, when

R₁₃ is: --CH₂ --O--CO--Ar₁, --CH₂ --S --CO--Ar₁, --CH₂ --O--Ar₁, --CH₂ --S--Ar₁, or --R₄ when --R₄ is --H;

then the ring of the R₁ (o) group must be substituted with Q₁ or benzofused; and provided that when

R₁ is (w),

g is 0,

J is --H,

m is 1,

T is --CO₂ H or --CO--NH--OH,

X₂ is O,

R₅ is benzyloxycarbonyl, and

ring C is benzo,

then R₃ cannot be --CO--R₁₃ when:

R₁₃ is --CH₂ --O--Ar₁ and

Ar₁ is 1-phenyl-3-chloro- or 3-trifluoromethyl-pyrazole-5-yl; or when

R₁₃ is --CH₂ --O--CO--Ar₁ and

Ar₁ is 2,6-dichlorophenyl.

Preferred forms of the R₁ group (a) for embodiments. A and B are: ##STR25##

Preferred forms of the R₁ group (b) are: ##STR26##

Preferred forms of the R₁ group (c) are: ##STR27## provided that when R₁ is (c1),

g is 0,

J is --H,

m is 1,

T is --CO₂ H,

X is N,

R₅ is benzyloxycarbonyl, and

R₆ is --H,

then R₃ cannot be --CO--R₁₃ when

R₁₃ is --CH₂ --O--Ar₁ and

Ar₁ is a chloro-substituted 1-phenyl-3-trifluoromethyl-pyrazole-5-yl, or when

R₁₃ is --CH₂ --O--CO--Ar₁ and

Ar₁ is 2,6-dichlorophenyl,

and when the 2-position of the scaffold ring is substituted with para-fluoro-phenyl;

Preferred forms of the R₁ group (d) are: ##STR28##

Preferred forms of the R₁ group (e) are: ##STR29## which is optionally benzofused; ##STR30## provided that when R₁ is (e4),

g is 0,

J is --H,

m is 1,

T is --CO₂ H,

R₅ is benzyloxycarbonyl, and

c is 1,

then R₆ cannot be --CO--R₁₃ when

R₁₃ is --CH₂ --O--Ar₁ and

Ar₁ is 1-phenyl-3-trifluoromethyl-pyrazole-5-yl, wherein the phenyl is optionally substituted with a chlorine atom; or when

R₁₃ is --CH₂ --O--CO--Ar₁ and

Ar₁ is 2,6-dichlorophenyl,

and when the 2-position of the scaffold ring is substituted with para-fluoro-phenyl; and also provided that when

R₁ is (e7),

g is 0,

J is --H,

m is 1,

T is --CO₂ H or --CO--NH--OH,

R₆ is a protective group for the N atom of an amino acid side chain residue, and

each c is 1,

then R₃ cannot be --CO--R₁₃ when

R₁ is: --CH₂ --O--CO--Ar₁, --CH₂ --S--CO--Ar₁, --CH₂ --O--Ar₁, or --CH₂ --S--Ar₁.

Preferred forms of the R₁ group (g) are: ##STR31##

Preferred forms of the R₁ group (h) are: ##STR32##

Preferred forms of the R₁ group (i) are: ##STR33##

Preferred forms of the R₁ group (j) are: ##STR34##

Preferred forms of the R₁ group (k) are ##STR35##

Preferred forms of the R₁ group (l) are: ##STR36##

Preferred forms of the R₁ group (m) are: ##STR37##

Preferred forms of the R₁ group (n) are: ##STR38##

Preferred forms of the R₁ group (o) are: ##STR39##

A preferred form of the R₁ group (o) of embodiment B is: ##STR40##

For embodiments A and B, preferred forms of the R₁ group (p) are: ##STR41##

Preferred forms of the R₁ group (q) are: ##STR42##

Preferred forms of the R₁ group (r) are: ##STR43##

Preferred forms of the R₁ group (s) are: ##STR44##

Preferred forms of the R₁ group (t) are: ##STR45##

Preferred forms of the R₁ group (v) are: ##STR46##

A preferred form of the R1 group (w) of embodiment B is: ##STR47## wherein X₂ is --O--, --S--, --SO₂ -- or --NH--.

The preferred compounds of embodiments A and B of this invention are those which employ formula α, wherein:

X₁ is CH;

g is O;

J is --H;

m is 0 or 1 and T is --Ar₃, --CO--CO₂ H, --CO₂ H or any bioisosteric replacement for --CO₂ H, or

m is 1 or 2 and T is --OH, --CF₃, or --CO₂ H;

more preferably m is 1 and T is --CO₂ H;

R₁ is ##STR48##

R₂₀ is ##STR49## wherein ring C is benzo;

R₃ is --CO--R₁₃, or ##STR50## most preferably R₃ is any one of 1), 2) or 3) as follows: 1) --CO--Ar₂, 2) --CO--R₉ where R_(s) is C₃₋₆ alkyl substituted with two Ar₁ groups or one Ar₁ group itself substituted with an Ar₁ group, --C₁₋₂ --Ar₁, --Cl, --CH₃, or --CF₃, or 3) --(CH₂)₁,2 --T₁ --R₉ where T₁ is --O-- or --S-- and R₉ is C₁₋₂ alkyl substituted with two Ar₁ groups or one Ar₁ group itself substituted with an Ar₁ group, C₁₋₂ --Ar₁, --Cl, --CH₃, or --CF₃ ;

R₄ is --H or --R₉ ;

T₁ is --O--, --S--, --CO--, --O--CO--, or --SO₂ --;

when R₁ is (a), (b), (k), or (m), R₅ is preferably --Ar₁ or C₁₋₄ --Ar₁ ;

when R₁ is (c), (e), (f), (o), or (r), R₅ is preferably--SO₂ --Ar₁, --SO₂ --R₉, or --CO--C₁₋₄ --Ar₁ ;

R₇ is --H and R₆ is C₁₋₄ --Ar₁ ;

R₁₀ is --H or a C₁₋₃ straight or branched alkyl group;

R₁₃ is --Ar₂ ;

Ar₁ is phenyl, naphthyl, pyridyl, benzothiazolyl, thienyl, benzothienyl, benzoxazolyl, 2-indanyl, or indolyl;

Ar₂ is preferably substituted with --Ar₁, or --C₁₋₄ --Ar₁ ;

Ar₃ is phenyl, thiophene, thiazole, pyridine, or oxazole; and

Q₁ is --R₉ or --(CH₂)₁₋₂ --T₁ --(CH₂)₁₋₃ --Ar₁ where T₁ is --O-- or --S--.

For preferred compounds which employ formula β, R₃₁ is R₉ and R₃₂ is (pp), wherein c is 1 or 2, X is C, J is H, m is 1 or 2, and T is --CO₂ H. In addition, the preferred R₃₀ groups are (rr) and (ss).

Preferred forms of (rr) are: ##STR51##

Preferred forms of (ss) are: ##STR52##

For preferred compounds which employ formula (w), Y₄ is --O-- or --S--, X₇ is --NH--, J is H, m and T are 2 and --CO₂ H or 1 and --CO--CO₂ H, and R₁₆ is (yy), (aaa), or (fff).

For preferred compounds which employ formula (hhh), Z₁ is carbonyl, J is M, f is 1 or 2, T is --CO₂ H, and R₁₆ is (ww), (xx), (yy), (aaa), or (fff).

In the preferred form of (ww), c is 2, R₆ is isopropyl, R₇ is H, Am is any natural amino acid, and R₅ is acetyl or benzyloxycarbonyl.

Preferred forms of (xx) are: ##STR53##

Preferred forms of (yy) are: ##STR54##

In the preferred forms of (aaa), d is 1 and R₅ is --H, --CO--O--R₉, --SO₂ --R₉, or --SO₂ --Ar₁.

Preferred forms of (fff) are: ##STR55##

In connection with this continuation-in-part, we now prefer the compounds of embodiment B of this invention which employ formula α, wherein:

X₁ is --CH;

g is O;

J is --H;

m is 0 or 1 and T is --CO--CO₂ H, or any bioisosteric replacement for --CO₂ H; or

m is 1 and T is --CO₂ H;

R₁ is selected from the group consisting of the following formulae, in which any ring may optionally be singly or multiply substituted at any carbon by Q₁, at any nitrogen by R₅, or at any atom by ═O, --OH, --CO₂ H, or halogen, and wherein (e) is optionally benzofused: ##STR56##

R₂₀ is ##STR57## and c is 1;

ring C is benzo optionally substituted with --C₁₋₃ alkyl, --O--C₁₋₃ alkyl, --Cl, --F or --CF₃ ;

R₃ is: --CO--R₁₃, or ##STR58## more preferably R₃ is any one of 1), 2) or 3) as follows: 1) --CO--Ar₂ ; ) --CO--R₉ where R₉ is C₁₋₅ alkyl substituted with an Ar₁ ; or 3) --CH₂ --T₁ --R₁ where T₁ is --O-- or --S-- and R₉ is C₁₋₂ alkyl substituted with one Ar₁ group;

R₄ is --H or --R₉ ;

T₁ is: --O--, --S--, --CO--, --O--CO--, or --SO₂ --;

when R₁ is (a) or (b), R₅ is preferably --H, and

when R₁ is (c), (e), (f), (o), (r), (w), (x) or (y), R₅ is preferably: --CO--Ar₁, --SO₂ --Ar₁, --CO--NH₂, --CO--NH--Ar₁, --CO--R₉, --CO--O--R₉, --SO₂ --R₉, or --CO--NH--R₉,

R₇ is --H and R₆ is --H, --R₉ or --Ar₁ ;

R₉ is C₁₋₆ straight or branched alkyl group optionally substituted with ═O and optionally substituted with --Ar₁ ;

R₁₀ is --H or a C₁₋₃ straight or branched alkyl group;

R₁₃ is: --H, --R₉, --Ar₂, or --CH₂ --T₁ --R₉,

more preferably where --Ar₂ is (hh) and where (hh) is optionally substituted singly or multiply with --C₁₋₆ alkyl, --O--C₁₋₆ alkyl, --NH--C₁₋₆ alkyl, --N--(C₁₋₆ alkyl)₂, --S--C₁₋₆ alkyl, --Cl, --F, --CF₃, or ##STR59##

Ar₁ is phenyl, naphthyl, pyridyl, benzothiazolyl, thienyl, benzothienyl, benzoxazolyl, 2-indanyl, or indolyl substituted with --O--C₁₋₃ alkyl, --NH--C₁₋₃ alkyl, --N--(C₁₋₃ alkyl)₂, --Cl, --F, --CF₃, --C₁₋₃ alkyl, or ##STR60## preferably where Ar₂ is: ##STR61## then

R₄ is --H, --Ar₁ or --R₉, wherein R₉ is --C₁₋₄ --Ar₁ ; and

Q₁ is --R₉ or --(CH₂)₀,1,2 --T₁ --(CH₂)₀,1,2 --Ar₁, wherein T₁ is --O-- or --S--;

each X is independently selected from the group consisting of ═N--, and ═CH--;

each X₂ is independently selected from the group consisting of --O--, --CH₂ --, --NH--, --S--, --SO--, and --SO₂ --;

each X₅ is independently selected from the group consisting of ##STR62## and

Z is C═O;

provided that when

R₁ is (f),

R₆ is an α-amino acid side chain residue, and

R₇ is --H,

then (aa1) and (aa2) must be substituted with Q₁ ; also provided that when

R₁ is (o),

g is 0,

J is --H,

m is 1,

R₆ is an α-amino acid side chain residue,

R₇ is H,

X₂ i s --CH₂ --, ##STR63## and

R₃ is ##STR64## or --CO--R₁₃, when

R₁₃ is: --CH₂ --O--CO--Ar₁, --CH₂ --S--CO--Ar₁, --CH₂ --O--Ar₁, --CH₂ --S--Ar₁, or --R₄ when --R₄ is --H;

then the ring of the R₁ (o) group must be substituted with Q₁ or benzofused; and provided that when

R₁ is (w),

g is 0,

J is --H,

m is 1,

T is --CO₂ H,

X₂ is O,

R₅ is benzyloxycarbonyl, and

ring C is benzo,

then R₆ cannot be --CO--R₁₃ when:

R₁₃ is --CH₂ --O--Ar₁ and

Ar₁ is 1-phenyl-3 -trifluoromethyl-pyrazole-5-yl, wherein the phenyl is optionally substituted with a chlorine atom;

or when R₁₃ is --CH₂ --O--CO--Ar₁, wherein Ar₁ is 2,6-dichlorophenyl.

A more preferred form of the R₁ group (a) is: ##STR65## optionally substituted with Q₁, wherein

R₅ is --H;

R₇ is --H; and

Z is C═O;

a more preferred form of the R₁ group (b) is: ##STR66## optionally substituted with Q₁, wherein

R₅ is --H;

R₇ is --H; and

Z is C═O;

more preferred forms of the R₁ group (c) are: ##STR67## provided that when R₁ is (c1),

g is 0,

J is --H,

m is 1,

T is --CO₂ H,

X is N,

R₅ is benzyloxycarbonyl, and

R₆ is --H,

then R₃ cannot be --CO--R₁₃ when

R₁₃ is --CH₂ --O--Ar₁ and

Ar₁ is 1-phenyl-3-trifluoromethyl-pyrazole-5-yl wherein the phenyl is optionally substituted with a chlorine atom; or when

R₁₃ is --CH₂ -O--CO--Ar₁, wherein

Ar₁ is 2,6-dichlorophenyl,

and wherein the 2-position of the scaffold ring is substituted with para-fluoro-phenyl; more preferred forms of the R₁ group (e) are: ##STR68## wherein c is 2; and ##STR69## which is optionally benzofused, wherein c is 1 or 2; provided that when R₁ is (e4),

g is 0,

J is --H,

m is 1,

T is --CO₂ H,

R₅ is benzyloxycarbonyl, and

c is 1,

then R₃ cannot be --CO--R₁₃ when

R₁₃ s --CH₂ --O--Ar₁ and

Ar₁ is 1-phenyl-3-trifluoromethyl-pyrazole-5-yl wherein the phenyl is optionally substituted with a chlorine atom; or when

R₁₃ is --CH₂ --O--CO--Ar₁, wherein

Ar₁ is 2,6-dichlorophenyl,

and wherein the 2-position of the scaffold ring is substituted with para-fluoro-phenyl; and also provided that when

R₁ is (e7),

g is 0,

J is --H,

m is 1,

T is --CO₂ H, --CO--NH--OH, or a bioisosteric replacement for --CO₂ H,

R₅ is a protective group for the N atom of an α-amino acid side chain residue, and

each c is 1,

then R₃ cannot be --CO--R₁₃ when R₁₃ is:

--CH₂ --O--CO--Ar₁,

--CH₂ --S--CO--Ar₁,

--CH₂ --O--Ar₁, or

--CH₂ --S--Ar₁.

a more preferred form of the R₁ group (f) is ##STR70##

a more preferred form of the R₁ group (g) is: ##STR71## wherein

R₂₀ is (aa1) optionally substituted singly or multiply with Q₁ ; and

Z is C═O;

a more preferred form of the R₁ group (h) is: ##STR72## wherein

R₂₀ is (aa1) optionally substituted singly or multiply with Q₁ ; and

Z is C═O;

more preferred forms of the R₁ group (o) are: ##STR73## wherein d is 1 or 2; and ##STR74##

more preferred forms of the R₁ group (r) are: ##STR75## optionally substituted with Q₁ ;

a more preferred form of the R₁ group (w) is: ##STR76## wherein

X₂ is: --NH--, --S--, --O--, or --SO₂ --;

optionally substituted with R₅ or Q₁ at X₂ when X₂ is --N--; and

ring C is benzo substituted with --C₁₋₃ alkyl, --O--C₁₋₃ alkyl, --Cl, --F or --CF₃.

The ICE inhibitors of another embodiment (C) of this invention are represented by the formula: ##STR77## wherein the ring is optionally substituted with one or more R groups, preferably 0, 1 or 2; and wherein:

R₁ is R₅ --(A)_(p) --;

R₅ is selected from the group consisting of: --H, --Ar₁, --CO--Ar₁, --SO₂ --Ar₁, --R₉, --CO--R₉, --CO--O--R₉, --SO₂ --R₉, ##STR78##

each A is independently selected from the group consisiting of any α-amino acid;

p is 0, 1, 2, 3 or 4;

Y is: --O--, --S-- or --NH;

R is: --H, --O--C₁₋₆ alkyl, --NH(C₁₋₆ alkyl), --N(C₁₋₆ alkyl)₂, --S--C₁₋₆ alkyl, --C₁₋₃ alkyl, or --Q₂ ;

each R₉ is a C₁₋₆ straight or branched alkyl group optionally singly or multiply substituted by --OH, --F, or ═O and optionally substituted with one or two Ar₁ groups;

each R₁₀ is independently selected from the group consisting of --H or a C₁₋₆ straight or branched alkyl group;

each T₁ is independently selected from the group consisting of: --CH═CM --, --O--, --S--, --SO--, --SO₂ --, --NR₁₀ --, --NR₁₀ --CO--, --CO--, --O--CO--, --CO--O--, --CO--NR₁₀ --, --O--CO--NR₁₀ --, --NR₁₀ --CO--O--, --NR₁₀ --CO--NR₁₀ --, --SO₂ --NR₁₀ --, --NR₁₀ --SO₂ --, and --NR₁₀ --SO₂ --NR₁₀ --,

each Ar₁ is a cyclic group independently selected from the set consisting of an aryl group which contains 6, 10, 12, or 14 carbon atoms and between 1 and 3 rings, a cycloalkyl group which contains between 3 and carbon atoms and between 1 and 3 rings, said cycloalkyl group being optionally benzofused, and a heterocycle group containing between 5 and 15 ring atoms and between 1 and 3 rings, said heterocycle group containing at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, said heterocycle group optionally containing one or more double bonds, said heterocycle group optionally comprising one or more aromatic rings, and said cyclic group optionally being singly or multiply substituted by: --NH₂, --CO₂ H, --Cl, --F, --Br, --I, --NO₂, --CN, ═O, --OH, -perfluoro C₁₋₃ alkyl, ##STR79## or --Q₁ ;

each Q₁ is independently selected from the group consisting of: --Ar₁, --R₉, --T₁ --R₉, and --(CH₂)₁,2,3 --T₁ --R₉ ;

each Q₁ is independently selected from the group consisting of --OH, --NH₂, --CO₂ H, --Cl, --F, --Br, --I, --NO₂, --CN, --CF₃, and ##STR80## provided that when --Ar₁ is substituted with a Q₁ group which comprises one or more additional --Ar₁ groups, said additional --Ar₁ groups are not substituted with Q₁.

Preferred compounds of embodiment C of this invention include but are not limited to: ##STR81##

Preferred compounds of embodiment C of this invention are also those in which each A is independently selected from the group consisting of the α-amino acids:

alanine,

histidine,

lysine,

phenylalanine,

proline,

tyrosine,

valine,

leucine,

isoleucine,

glutamine,

methionine,

homoproline,

3-(2-thienyl) alanine, and

3-(3-thienyl) alanine.

The ICE inhibitors of another embodiment (D) of this invention are represented by the formula: ##STR82## wherein:

R₁ is R₅ --(A)_(p) --;

each T₁ is independently selected from the group consisting of:

--CH═CH--,

--O--,

--S--,

--SO--,

--SO₂ --,

--NR₁₀ --,

--NR₁₀ --CO--,

--CO--,

--O--CO--,

--CO--O--,

--CO--NR₁₀ --,

--O--CO--NR₁₀,

--NR₁₀ --CO--O--,

--NR₁₀ --CO--NR₁₀ --,

--SO₂ --NR₁₀ --,

--NR₁₀ --SO₂ --, and

--NR₁₀ --SO₂ --NR₁₀ --;

R₅ is selected from the group consisting of:

--H,

--Ar₁,

--CO--Ar₁,

--SO₂ --Ar₁,

--R₉,

--CO--R₉,

--CO--O--R₉,

--SO₂ --R₉, ##STR83##

each A is independently selected from the group consisiting of any α-amino acid;

p is 0, 1, 2, 3 or 4;

each R₉ is a C₁₋₆ straight or branched alkyl group optionally singly or multiply substituted by --OH, --F, or ═O and optionally substituted with an Ar₁ group;

each R₁₀ is independently selected from the group consisting of --H or a C₁₋₆ straight or branched alkyl group;

Ar₁ is a cyclic group independently selected from the set consisting of an aryl group which contains 6, 10, 12, or 14 carbon atoms and between 1 and 3 rings, a cycloalkyl group which contains between 3 and 15 carbon atoms and between 1 and 3 rings, said cycloalkyl group being optionally benzofused, and a heterocycle group containing between 5 and 15 ring atoms and between 1 and 3 rings, said heterocycle group containing at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, said heterocycle group optionally containing one or more double bonds, said heterocycle group optionally comprising one or more aromatic rings, and said cyclic group optionally being singly or multiply substituted by --NH₂, --CO₂ H, --Cl, --F, --Br, --I, --NO₂, --CH, ═O, --OH, -perfluoro C₁₋₃ alkyl, or ##STR84##

Preferred compounds of embodiment D of this invention are those in which R₉ is a C₁₋₄ straight or branched alkyl substituted with Ar₁ when Ar₁ is phenyl.

Preferred compounds of embodiment D of this invention include but are not limited to: ##STR85##

Preferred compounds of embodiment D of this invention are also those in which A is independently selected from the group consisting of the α-amino acids:

alanine,

histidine,

lysine,

phenylalanine,

proline,

tyrosine,

valine,

leucine,

isoleucine,

glutamine,

methionine,

homoproline,

3-(2-thienyl) alanine, and

3-(3-thienyl) alanine.

The compounds of this invention having a molecular weight of less than or equal to about 700 Daltons, and more preferably between about 400 and 600 Daltons, are prefered. These preferred compounds may be readily absorbed by the bloodstream of patients upon oral administration. This oral availability makes such compounds excellent agents for orally-administered treatment and prevention regimens against IL-1 mediated diseases.

The ICE inhibitors of this invention may be synthesized using conventional techniques. Advantageously, these compounds are conveniently synthesized from readily available starting materials.

The compounds of this invention are among the most readily synthesized ICE inhibitors known. Previously described ICE inhibitors often contain four or more chiral centers and numerous peptide linkages. The relative ease with which the compounds of this invention can be synthesized represents an enormous advantage in the large scale production of these compounds.

It should be understood that the compounds of this invention may exist in various equilibrium forms, depending on conditions including choice of solvent, pH, and others known to the practitioner skilled in the art. All such forms of these compounds are expressly included in the present invention. In particular, many of the compounds of this invention, especially those which contain aldehyde or ketone groups in R₃ and carboxylic acid groups in T, may take hemi-ketal (or hemi-acetal) or hydrated forms, as depicted below: ##STR86##

Depending on the choice of solvent and other conditions known to the practitioner skilled in the art, compounds of this invention may also take acyloxy ketal, acyloxy acetal, ketal or acetal form: ##STR87##

In addition, it should be understood that the equilibrium forms of the compounds of this invention may include tautomeric forms. All such forms of these compounds are expressly included in the present invention.

It should be understood that the compounds of this invention may be modified by appropriate functionalities to enhance selective biological properties. Such modifications are known in the art and include those which increase biological penetration into a given biological system (e.g., blood, lymphatic system, central nervous system), increase oral availability, increase solubility to allow administration by injection, alter metabolism and alter rate of excretion. In addition, the compounds may be altered to pro-drug form such that the desired compound is created in the body of the patient as the result of the action of metabolic or other biochemical processes on the pro-drug. Such pro-drug forms may include ketal or acetal forms of compounds which contain ketone or aldehyde groups, especially where they occur in the R₃ group of the compounds of this invention.

The compounds of this invention are excellent ligands for ICE. Accordingly, these compounds are capable of targeting and inhibiting events in IL-1 mediated diseases, such as the conversion of precursor IL-1β to mature IL-1β and, thus, the ultimate activity of that protein in inflammatory diseases, autoimmune diseases and neurodegenerative diseases. For example, the compounds of this invention inhibit the conversion of precursor IL-1β to mature IL-1β by inhibiting ICE. Because ICE is essential for the production of mature In-1, inhibition of that enzyme effectively blocks initiation of IL-1 mediated physiological effects and symptoms, such as inflammation, by inhibiting the production of mature IL-1. Thus, by inhibiting IL-1β precursor activity, the compounds of this invention effectively function as In-1 inhibitors.

The compounds of this invention may be employed in a conventional manner for the treatment of diseases which are mediated by IL-1. Such methods of treatment, their dosage levels and requirements may be selected by those of ordinary skill in the art from available methods and techniques. For example, a compound of this invention may be combined with a pharmaceutically acceptable adjuvant for administration to a patient suffering from an IL-1 mediated disease in a pharmaceutically acceptable manner and in an amount effective to lessen the severity of that disease.

Alternatively, the compounds of this invention may be used in compositions and methods for treating or protecting individuals against IL-1 mediated diseases over extended periods of time. The compounds may be employed in such compositions either alone or together with other compounds of this invention in a manner consistent with the conventional utilization of ICE inhibitors in pharmaceutical compositions. For example, a compound of this invention may be combined with pharmaceutically acceptable adjuvants conventionally employed in vaccines and administered in prophylactically effective amounts to protect individuals over an extended period time against IL-1 mediated diseases.

The compounds of this invention may also be co-administered with other ICE inhibitors to increase the effect of therapy or prophylaxis against various IL-1-mediated diseases.

In addition, the compounds of this invention may be used in combination either conventional anti-inflammatory agents or with matrix metalloprotease inhibitors, lipoxygenase inhibitors and antagonists of cytokines other than IL-1β.

The compounds of this invention can also be administered in combination with immunomodulators (e.g., bropirimine, anti-human alpha interferon antibody, IL-2, GM-CSF, methionine enkephalin, interferon alpha, diethyldithiocarbamate, tumor necrosis factor, naltrexone and rEPO) or with prostaglandins, to prevent or combat IL-1-mediated disease symptoms such as inflammation.

When the compounds of this invention are administered in combination therapies with other agents, they may be administered sequentially or concurrently to the patient. Alternatively, pharmaceutical or prophylactic compositions according to this invention may be comprised of a combination of an ICE inhibitor of this invention and another therapeutic or prophylactic agent.

Pharmaceutical compositions of this invention comprise any of the compounds of the present invention, and pharmaceutically acceptable salts thereof, with any pharmaceutically acceptable carrier, adjuvant or vehicle. Pharmaceutically acceptable carriers, adjuvants and vehicles that may be used in the pharmaceutical compositions of this invention include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride-mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol and wool fat.

The pharmaceutical compositions of this invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. We prefer oral administration. The pharmaceutical compositions of this invention may contain any conventional non-toxic pharmaceutically-acceptable carriers, adjuvants or vehicles. The term parenteral as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intra-articular, intrasynovial, intrasternal, intrathecal, intralesional and intracranial injection or infusion techniques.

The pharmaceutical compositions may be in the form of a sterile injectable preparation, for example, as a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example, Tween 80) and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are mannitol, water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or diglycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant such as Ph. Helv or a similar alcohol.

The pharmaceutical compositions of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, and aqueous suspensions and solutions. In the case of tablets for oral use, carriers which are commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried corn starch. When aqueous suspensions are administered orally, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening and/or flavoring and/or coloring agents may be added.

The pharmaceutical compositions of this invention may also be administered in the form of suppositories for rectal administration. These compositions can be prepared by mixing a compound of this invention with a suitable non-irritating excipient which is solid at room temperature but liquid at the rectal temperature and therefore will melt in the rectum to release the active components. Such materials include, but are not limited to, cocoa butter, beeswax and polyethylene glycols.

Topical administration of the pharmaceutical compositions of this invention is especially useful when the desired treatment involves areas or organs readily accessible by topical application. For application topically to the skin, the pharmaceutical composition should be formulated with a suitable ointment containing the active components suspended or dissolved in a carrier. Carriers for topical administration of the compounds of this invention include, but are not limited to, mineral oil, liquid petroleum, white petroleum, propylene glycol, polyoxyethylene polyoxypropylene compound, emulsifying wax and water. Alternatively, the pharmaceutical composition can be formulated with a suitable lotion or cream containing the active compound suspended or dissolved in a carrier. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water. The pharmaceutical compositions of this invention may also be topically applied to the lower intestinal tract by rectal suppository formulation or in a suitable enema formulation. Topically-transdermal patches are also included in this invention.

The pharmaceutical compositions of this invention may be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.

The IL-1 mediated diseases which may be treated or prevented by the compounds of this invention include, but are not limited to, inflammatory diseases, autoimmune diseases and neurodegenerative diseases.

Inflammatory diseases which may be treated or prevented include, for example, septic shock, septicemia, and adult respiratory distress syndrome. Target autoimmune diseases include, for example, rheumatoid, arthritis, systemic lupus erythematosus, scleroderma, chronic thyroiditis, Graves' disease, autoimmune gastritis, insulin-dependent diabetes mellitus, autoimmune hemolytic anemia, autoimmune neutropenia, thrombocytopenia, chronic active hepatitis, myasthenia gravis and multiple sclerosis. And target neurodegenerative diseases include, for example, amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, and primary lateral sclerosis. The ICE inhibitors of this invention may also be used to promote wound healing. And the ICE inhibitors of this invention may be used to treat infectious diseases.

Although this invention focuses on the use of the compounds disclosed herein for preventing and treating IL-1-mediated diseases, the compounds of this invention can also be used as inhibitory agents for other cysteine proteases.

The compounds of this invention are also useful as commercial reagents which effectively bind to ICE or other cysteine proteases. As commercial reagents, the compounds of this invention, and their derivatives, may be used to block proteolysis of a target peptide or may be derivatized to bind to a stable resin as a tethered substrate for affinity chromatography applications. These and other uses which characterize commercial cysteine protease inhibitors will be evident to those of ordinary skill in the art.

In order that this invention be more fully understood, the following examples are set forth. These examples are for the purpose of illustration only and are not to be construed as limiting the scope of the invention in any way.

EXAMPLE 1

The following example demonstrates a process of drug design which embodies the present invention:

Step 1) Pick 2 hydrogen bonding moieties of ICE, here, the backbone C═O and N--H of Arg-341.

Step 2) Pick a scaffold, here, a pyridone derivative, and confirm that the hydrogen bonding moieties of the scaffold are capable of forming satisfactory hydrogen bonds with the hydrogen bonding moieties selected in step 1. This confirmation is performed by using molecular mechanics techniques to minimize the scaffold fragment in the context of the active site of ICE. ##STR88##

Step 3) Pick a hydrophobic pocket, here, S2, as next target and a hydrophobic moiety, here, benzene. Minimize the benzene group within the S2 pocket to assure that substantial hydrophobic overlap is obtained. ##STR89##

Step 4) Pick another hydrophobic pocket, here, S4, as the next target and a hydrophobic moiety, here, benzene. Minimize the benzene group within the S4 pocket to ensure that substantial hydrophobic overlap is obtained. ##STR90##

Step 5) Fill the S1 polar pocket with an electronegative moiety, here, a carboxylate sidechain provided by aspartic acid in which the C-terminus has been reduced to an aldehyde. Minimize to ensure that the carboxylate sidechain retains a favorable electrostatic interaction with the S1 polar pocket. ##STR91##

Step 6) Link the scaffold with the moieties from steps 3, 4, and 5, preferably using the minimum number of bonds consistent with a chemically reasonable structure. Minimize the entire composite molecule in the active site of ICE. ##STR92##

Step 7) Evaluate the energy of the molecule when it has the conformation necessary for binding to ICE. Then minimize and reevaluate the energy--this is the free conformation energy. The strain energy for binding of the potential inhibitor to ICE is the difference between the free conformation energy and the bound conformation energy. The strain energy should be less than about 10 kcal/mol. In this case the bound conformation energy is -1.6 kcal/mol and the free conformation energy is -11.7 kcal/mol, for a strain energy of 10.1 kcal/mol.

Step 8) The inhibitor designed using the above steps has been made and has been show to have a K_(i) of 150 nM.

EXAMPLE 2

We obtained inhibition constants (K_(i)) and IC₅₀ values for several compounds of this invention using the three methods described below:

1. Enzyme assay with UV-visible substrate

This assay is run using an Succinyl-Tyr-Val-Ala-Asp-pNitroanilide substrate. Synthesis of analogous substrates is described by L. A. Reiter (Int. J. Peptide Protein Res. 43, 87-96 (1994)). The assay mixture contains:

    ______________________________________                                         65 μl                                                                             buffer (10 mM Tris 1 mM DTT, 0.1% CHAPS @pH 8.1)                         10 μl                                                                             ICE (50 nM final concentration to give a rate of .sup.˜ 1                mOD/min)                                                                 5 μl                                                                              DMSO/Inhibitor mixture                                                   20 μl                                                                             400 μM Substrate (80 μM final concentration)                       100 μl                                                                            total reaction volume                                                    ______________________________________                                    

The visible ICE assay is run in a 96-well microtiter plate. Buffer, ICE and DMSO (if inhibitor is present) are added to the wells in the order listed. The components are left to incubate at room temperature for 15 minutes starting at the time that all components are present in all wells. The microtiter plate reader is set to incubate at 37° C. After the 15 minute incubation, substrate is added directly to the wells and the reaction is monitored by following the release of the chromophore (pNA) at 405-603 nm at 37° C. for 20 minutes. A linear fit of the data is performed and the rate is calculated in mOD/min. DMSO is only present during experiments involving inhibitors, buffer is used to make up the volume to 100 μl in the other experiments.

2. Enzyme Assay with Fluorescent Substrate

This assay is run essentially according to Thornberry et al. (Nature 356: 768-774 (1992)), using substrate 17 referenced in that article. The substrate is: Acetyl-Tyr-Val-Ala-Asp-amino-4-methylcoumarin (AMC). The following components are mixed:

    ______________________________________                                         65 μl                                                                             buffer (10 mM Tris, 1 mM DTT, 0.1% CHAPS @pH 8.1)                        10 μl                                                                             ICE (2-10 nM final concentration)                                        5 μl                                                                              DMSO/inhibitor solution                                                  20 μl                                                                             150 μM Substrate (30 μM final)                                     100 μl                                                                            total reaction volume                                                    ______________________________________                                    

The assay is run in a 96 well microtiter plate. Buffer and ICE are added to the wells. The components are left to incubate at 37° C. for 15 minutes in a temperature-controlled wellplate. After the 15 minute incubation, the reaction is started by adding substrate directly to the wells and the reaction is monitored @37° C. for 30 minutes by following the release of the AMC fluorophore using an excitation wavelength for 380 nm and an emission wavelength of 460 nm. A linear fit of the data for each well is performed and a rate is determined in fluorescence units per second.

For determination of enzyme inhibition constants (K_(i)) or the mode of inhibition (competitive, uncompetitive or noncompetitive), the rate data determined in the enzyme assays at varying inhibitor concentrations are computer-fit to standard enzyme kinetic equations (see I. H. Segel, Enzyme Kinetics, Wiley-Interscience, 1975).

3. Cell assay

IL-1β Assay with a Mixed Population of Human Peripheral Blood Mononuclear Cells (PBMC) or Enriched Adherent Mononuclear Cells

Processing of pre-IL-1β by ICE can be measured in cell culture using a variety of cell sources. Human PBMC obtained from healthy donors provides a mixed population of lymphocyte subtypes and mononuclear cells that produce a spectrum of interleukins and cytokines in response to many classes of physiological stimulators. Adherent mononuclear cells from PBMC provides an enriched source of normal monocytes for selective studies of cytokine production by activated cells.

Experimental Procedure:

An initial dilution series of test compound in DMSO or ethanol is prepared, with a subsequent dilution into RPMI-10% FBS media (containing 2 mM L-glutamine, 10 mM HEPES, 50 U and 50 ug/ml pen/strep) respectively to yield drugs at 4x the final test concentration containing 0.4% DMSO or 0.4% ethanol. The final concentration of DMSO is 0.1% for all drug dilutions. A concentration titration which brackets the apparent K_(i) for a test compound determined in an ICE inhibition assay is generally used for the primary compound screen.

We generally test 5-6 compound dilutions and have performed the cellular component of the assay in duplicate, with duplicate ELISA determinations on each cell culture supernatant.

PBMC Isolation and IL-1 Assay:

Buffy coat cells isolated from one pint human blood (yielding 40-45 ml final volume plasma plus cells) are diluted with media to 80 ml and LeukoPREP separation tubes (Becton Dickinson) are each overlaid with 10 ml of cell suspension. After 15 min centrifugation at 1500-1800 xg, the plasma/media layer is aspirated and then the mononuclear cell layer is collected with a Pasteur pipette and transferred to a 15 ml conical centrifuge tube (Corning). Media is added to bring the volume to 15 ml, gently mix the cells by inversion and centrifuge at 300 xg for 15 min. Resuspend the PBMC pellet in a small volume of media, count cells and adjust to 6×10⁶ cells/ml.

For the cellular assay, add 1.0 ml of the cell suspension to each well of a 24-well flat bottom tissue culture plate (Corning), 0.5 ml test compound dilution and 0.5 ml LPS solution (Sigma #L-3012; 20 ng/ml solution prepared in complete RPMI media; final LPS concentration 5 ng/ml). The 0.5 ml additions of test compound and LPS are usually sufficient to mix the contents of the wells. Three control mixtures are run per experiment, with either LPS alone, solvent vehicle control, and/or additional media to adjust the final culture volume to 2.0 ml. The cell cultures are incubated for 16-18 hr at 37° C. in the presence of 5% CO₂.

At the end of the incubation period, cells are harvested and transferred to 15 ml conical centrifuge tubes. After centrifugation for 10 min at 200 xg, supernatants are harvested and transferred to 1.5 ml Eppendorf tubes. It may be noted that the cell pellet may be utilized for a biochemical evaluation of pre-IL-1g and/or mature IL-1β content in cytosol extracts by western blotting or ELISA with pre-IL-1β specific antisera.

Isolation of Adherent Mononuclear cells:

PBMC are isolated and prepared as described above. Media (1.0 ml) is first added to wells followed by 0.5 ml of the PBMC suspension. After a one hour incubation, plates are gently shaken and nonadherent cells aspirated from each well. Wells are then gently washed three times with 1.0 ml of media and final resuspended in 1.0 ml media. The enrichment for adherent cells generally yields 2.5-3.0×10⁵ cells per well. The addition of test compounds, LPS, cell incubation conditions and processing of supernatants proceeds as described above.

ELISA:

We have used Quantikine kits (R&D Systems) for measurement of mature IL-1β. Assays are performed according to the manufacturer's directions. Mature IL-1β levels of about 1-3 ng/ml in both PBMC and adherent mononuclear cell positive controls are observed. ELISA assays are performed on 1:5, 1:10 and 1:20 dilutions of supernatants from LPS-positive controls to select the optimal dilution for supernatants in the test panel.

The inhibitory potency of the compounds can be represented by an IC₅₀ value, which is the concentration of inhibitor at which 50% of mature IL-1β is detected in the supernatant as compared to the positive controls.

The following K_(i) and IC₅₀ values were determined for compounds A through N using the indicated assays. Structures for compounds A through N follow this table.

    ______________________________________                                                 K.sub.i (μM), by indicated assay:                                             UV-visible   Fluorescence                                                                             Cell                                          Compound  K.sub.i (μM)                                                                             K.sub.i (μM)                                                                          IC.sub.50 (μM)                             ______________________________________                                         A         5.5                    25.0                                          B         8.6                    20.0                                          C         10                     >30                                           D         4.7                                                                  E         3.2                                                                  F         0.15                   2-4                                           G         4.8                                                                  H         0.023        0.0047     6-11                                         I         0.0072       0.0052    2.6                                           J         0.0012       0.0039    5-7                                           K         0.010        0.002      2-11                                         L         0.014                                                                M         0.15                                                                 N         0.95                                                                 ______________________________________                                    

Structures of compounds A through N: ##STR93##

EXAMPLE 3

Compounds of Example 2 were synthesized as follows:

H. N-(N-Acetyl-tyrosinyl-valinyl-pipecolyl)-3-amino-4-oxobutanoic acid Step A. N-(N-tert-Butoxycarbonylpipecolyl)-4-amino-5-benzyloxy-2-oxotetrahydrofura

Reaction of N-tert-butoxycarbonylpipecolic acid (460 mg, 2.0 mmol) and N-allyloxycarbonyl-4-amino-5-benzyloxy-2-oxotetrahydrofuran (530 mg, 1.82 mmol) was carried out by a method analogous to that reported by Chapman (Bioorg. & Med. Chem. Lett. 1992, 2, 613-618.) to give 654 mg of the title compound.

1H NMR (500 MHz, CDCl₃ (existing as rotomers)) 7.35 (m, 5H), 6.88 (br. s, 1H), 4.9-4.45 (m, 4H), 3.95 (br. m, 2H), 3.06 (m, 1H), 2.9 (m, 1H), 2.7 (br. m, 1H), 2.45 (m, 1H), 2.2 (m, 1H), 1.7-1.5 (m, 3H), 1.45 (two s, 9H).

Step B. N-Pipecolyl-4-amino-5-benzyloxy-2-oxotetrahydrofuran

N-(N-tert-Butoxycarbonylpipecolyl)-4-amino-5-benzyloxy-2-oxo-tetrahydrofuran (654 mg) was dissolved in 15 ml of 25% trifluoroacetic acid in dichloromethane and stirred at room temperature. The mixture was concentrated to give a gummy residue. The residue was dissolved in dichloromethane and washed with 10% sodium bicarbonate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to give 422 mg of the title compound as a beige solid.

1H NMR (500 MHz, CDCl₃) 7.38 (m, 5H), 7.15 (d, 1H), 5.55 (d, 1H), 4.95-4.8 (m, 1H), 4.78 (m, 1H), 4.65 (d, 1H), 4.45 (m, 1H), 3.2 (m, 0.5H), 3.05 (m, 0.5H), 2.95 (m, 0.5H), 2.85 (m, 0.5H), 2.65 (m, 1H), 2.55-2.38 (m, 1H), 1.95 (m, 1H), 1.8 (m, 1H), 1.6 (m, 2H), 1.38 (m, 2H).

Step C. N-(N-Acetyl-tyrosinyl-valinyl-pipecolyl)-4-amino-5-benzyloxy-2-oxotetrahydrofuran

N-Acetyl-tyrosinyl-valine (464 mg, 1.44 mmol) and N-Pipecolyl-4-amino-5-benzyloxy-2-oxotetrahydrofuran (412 mg, 1.3 mmol) were dissolved in 5 ml each of dimethylformamide and dichloromethane and cooled to 0° C. To the cooled solution was added 1-hydroxybenzotriazole (HOBT; 210 mg, 1.56 mmol) followed by the addition of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (EDC; 326 mg, 1.7 mmol). After stirring for 18 hours, the mixture was diluted with ethyl acetate and washed with water, 10% sodium hydrogen sulfate, 10% sodium bicarbonate, and water. The organic layer was concentrated to give a crude solid that was purified by flash chromatography (SiO₂) eluting with 94:6:1 (dichloromethane:isopropanol:pyridine) to give 370 mg of the title compound.

1H NMR (500 MHz, CD₃ OD (existing as diastereomers as well as rotomers)) 7.35 (m, 5H), 7.05 (m, 2H), 6.68 (m, 2H), 5.65 & 5.25 (m, 1H), 4.9-3.95 (m, 8H), 3.4-2.6 (m, 4H), 2.5-2.1 (m, 1H), 1.98 (s, 1H), 1.9 (s, 1H), 1.85 (s, 1H), 1.8-1.6 (m, 2H), 1.55-1.3 (m, 4H), 0.95-0.85 (m, 6H).

Step D. N-(N-Acetyl-tyrosinyl-valinyl-pipecolyl)-3-amino-4-oxobutanoic acid

To a solution of 100 mg of N-(N-Acetyl-tyrosinyl-valinyl-pipecolyl)-4-amino-5-benzyloxy-2-oxotetrahydrofuran in 10 ml of methanol was added 60 mg of Pd(OH)₂ on carbon and the mixture placed under an atmosphere of hydrogen via a balloon. The mixture was filtered through Celite and concentrated providing a white solid. This crude solid was dissolved in 2 ml of methanol and triturated with diethyl ether affording 26 mg of the title compound.

1H NMR (500 MHz, CD₃ OD (existing as diastereomers as well as rotomers)) 7.1 (m, 2H), 6.7 (m, 2H), 5.2 (br. m, 1H), 4.8-3.6 (m, 6H), 3.2-2.5 (m, 4H), 2.5-2.1 (m, 1H), 1.95 (three s, 3H), 1.9-1.3 (m, 6H), 1.1-0.7 (m, 6H).

The following compounds were prepared by a method analogous to that reported for H:

J. N-[N-Acetyl-tyrosinyl-valinyl-(4-hydroxyprolinyl)]-3-amino-4-oxobutanoic acid

Substitute N-tert-butoxycarbonyl-4-benzyloxyproline for N-tert-butoxycarbonylpipecolic acid.

L. N-[2-(N-Acetyl-tyrosinyl-valinyl)-(S)-1,2,3,4-tetrahydroisoquinoline-3-carbonyl]-3-amino-oxobutanoic acid

Substitute (S)-N-tert-butoxycarbonyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid for N-tert-butoxycarbonylpipecolic acid.

I. N-(N-Acetyl-tyrosinyl-valinyl-(4-phenoxyprolinyl))-3-amino-4-oxobutanoic acid Step A. N-tert-Butoxycarbonyl-4-phenoxyproline methyl ester

To a cooled solution (0° C.) of N-tert-butoxy-cis-4-hydroxyproline (2-0 g, 8.15 mmol), phenol (0.77 g, 8.15 mmol), and triphenylphosphine (2.14 g, 8.15 mmol) in 20 ml of tetrahydrofuran was added diethyl azodicarboxylate (1.4 ml, 9 mmol) dropwise over 30 minutes. The reaction was stirred at room temperature for 16 hrs. then concentrated to give a viscous residue. The crude residue was purified by flash chromatography (SiO₂) eluting with 3:7 (ethyl acetate:hexane) to give 1.89 g of the title compound.

1H NMR (500 MHz, CDCl₃) 7.3 (m, 2H), 6.95 (m, 1H), 6.85 (d, 2H), 4.9 (m br., 1H), 4.55-4.15 (m, 2H), 3.88-3.65 (m, 1H), 3.70 (s, 3H), 2.58 (m, 1H), 2.22 (m, 1H), 1.4 (3×s, 9H).

Step B. 4-Phenoxyproline methyl ester hydrochloride

To a cooled solution (ice bath) of N-tert-Butoxycarbonyl-4-phenoxyproline methyl ester (0.6 g) in 20 ml of ethyl acetate was bubbled anhydrous hydrogen chloride until saturated. The mixture was warmed to room temperature and stirred for 3 hrs. then concentrated to give 480 mg of the title compound.

1H NMR (500 MHz, CDCl₃), 7.22 (m, 2H), 6.95 (m 1H), 6.83 (m, 2H), 5.1 (br., 1H), 4.6 (br. m, 1H), 4.06 (br. m, 1H), 3.75 (s, 3H), 3.55 (br. m, 1H), 2.58 (m, 2H).

Step C. N-Acetyl-tyrosinyl-valinyl-(4-phenoxy)proline methyl ester

N-Acetyl-tyrosinyl-valine (0.524 g, 1.63 mmol) and 4-phenoxyproline methyl ester (0.381 g, 1.48 mmol) were dissolved in 4 ml each of dimethylformamide and dichloromethane and cooled to 0° C. To the cooled solution was added diisopropylethylamine (258 ul, 1.86 mmol), HOBT (0.24 g, 1.78 mmol), and EDC (0.37 g, 1.92 mmol) and the reaction was stirred for 18 hrs. The mixture was diluted with 400 ml of ethyl acetate and washed with water, 10% sodium hydrogen sulfate, 10% sodium bicarbonate, and water. The organic layer was concentrated to give a residue that was purified by flash chromatography (SiO₂) eluting with 94:6:1 (CH2Cl2:i-PrOH:Pyridine) to afford 360 mg of the title compound.

1H NMR (500 MHz, CDCl₃ (existing as rotomers)) 7.3 (m, 2H), 7.05 (m, 1H), 6.95 (d, 2H), 6.9-6.2 (4×d, 4H), 5.05 (br. s, 1H), 4.7-3.94 (m, 5H), 2.93 (m, 1H), 2.82 (m, 1H), 2.65 (m, 1H), 2.2 (m, 1H), 2.05 (m, 1H), 1.95 (s, 3H), 1.86, (m, 1H), 0.98 (d, 3H), 0.88 (d, 3H).

Step D. N-Acetyl-tyrosinyl-valinyl-(4-phenoxy)proline

Lithium hydroxide (57 mg, 1.37 mmol) was added to a solution of N-Acetyl-tyrosinyl-valinyl-(4-phenoxy)proline methyl ester (360 mg, 0.685 mmol) dissolved in 8 ml of tetrahydrofuran/water (1:1) and stirred at room temperature for 1 hour. The mixture was acidified with 10% hydrochloric acid giving a white precipitate that was collected to give 175 mg of the title compound.

1H NMR (500 MHz, DMSO-d6) 9.2 (br. s, 1H), 8.05-7.95 (m, 2H), 7.3 (m, 1H), 7.0-6.9 (m, 4H), 6.65 (d, 2H), 4.42 (m, 1H), 4.35 (m, 1H), 4.05-3.95 (m, 2H), 3.3 (br. s, 2H), 2.75 (m, 1H), 2.55-2.38 (m, 2H), 2.2 (m, 1H), 2.0 (m, 1H), 1.7 (s, 3H), 0.95 (d, 3H), 0.85 (d, 3H).

Step E. N-[N-Acetyl-tyrosinyl-valinyl-(4-phenoxy)prolinyl]-4-amino-5-benzyloxy-2-oxotetrahydrofuran

The title compound was prepared by the method reported for compound H, step A, by reaction of N-acetyl-tyrosinyl-valinyl-(4-phenoxy)proline and N-allyloxycarbonyl-4-amino-5-benzyloxytetrahydrofuran.

1H NMR (500 MHz, CDCl₃ (existing as a 1:1 diastereomer mixture of the hemiacetal)) 7.8-6.3 (m, 17H), 5.6 (d, 1H), 5.1-4.15 (m, 5H), 4.15-3.75 (m, 2H), 2.95-2.15 (m, 5H), 2.15-1.95 (m, 1H), 1.9-1.85 (2×s, 3H), 1.1-0.75 (m, 6H).

Step F. N-[N-Acetyl-tyrosinyl-valinyl-(4-phenoxy)prolinyl]-3-amino-4-oxobutanoic acid

The title compound was prepared by the hydrogenolysis procedure reported for compound H, step D.

1H NMR (500 MHz, CD₃ OD (existing as a 1:1 diastereomer mixture of the hemiacetal)) 7.25 (m, 2H), 7.10-6.85 (m, 5H), 6.65 (d, 2H), 5.1 (br. m, 1H), 4.65-4.05 (m, 5H), 4.0-3.40 (m, 2H), 2.95-2.35 (m, 5H), 2.25 (m, 1H), 2.05 (m, 1H), 1.85 (s, 3H), 1.0 (d, 3H), 0.95 (d, 3H).

K. N-[N-Acetyl-tyrosinyl-valinyl-(4-benzyloxy)prolinyl]-3-amino-4-oxobutanoic acid Step A. N-(N-Allyloxycarbonyl-4-benzyloxyprolinyl)-3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone

The title compound was prepared by the reaction of N-allyloxycarbonyl-4-benzyloxyproline and 3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone (T. L. Graybill et. al., Abstracts of papers, 206th National Meeting of the American Chemical Society, Abstract MEDI-235. Chicago, Ill. (1993)) under similar peptide coupling conditions as reported above (compound H; Step C).

1H NMR (500 MHz, CDCl₃) 9.05 (br. s, 1H), 7.85 (br. m, 1H), 7.4-7.2 (m, 5H), 7.15 (br. s, 1H), 6.55 (br. s, 1H), 5.9 (m, 1H), 5.1-4.9 (br. m, 2H), 4.65-4.4 (m, 4H), 4.2 (br. m, 1H), 3.75-3.5 (m, 2H), 2.75-2.55 (m, 2H), 2.5 (br. m, 1H), 2.25 (br. m, 1H) 1.4 (s, 9H).

Step B. N-(N-Acetyl-tyrosinyl-valinyl-(4-benzyloxyprolinyl))-3-amino-4oxobutanoic acid tert-butyl ester semicarbazone

The title compound was prepared by reaction of N-acetyl-tyrosinyl-valine and N-(N-allyloxycarbonyl-4-benzyloxyprolinyl)-3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone by reaction conditions reported for compound H, step A.

1H NMR (500 MHz, CD₃ OD) 7.35-7.2 (m, 6H), 7.0 (d, 2H), 6.65 (d, 2H), 4.85 (m, 1H), 4.6-4.45 (m, 4H), 4.3 (br. m, 1H), 4.15 (m, 1H), 3.7 (m, 1H), 2.95 (m, IH), 2.75-2.6 (m, 3H), 2.35 (m, 1H), 2.1 (m, 1H), 1.9 (s, 3H), 1.4 (s, 9H), 0.95 (d, 3H), 0.90 (s, 3H).

Step C. N-(N-Acetyl-tyrosinyl-valinyl-(4-benzyloxyprolinyl))-3-amino-4oxobutanoic acid

N-(N-Acetyl-tyrosinyl-valinyl-(4-benzyloxyprolinyl))-3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone (270 mg) was dissolved into 10 ml of 25% trifluoroacetic acid in dichloromethane and stirred at room temperature for 3 hours. The mixture was concentrated to give a solid residue. The residue was dissolved into a 10 ml mixture of methanol:acetic acid:37% formaldehyde (3:1:1) and stirred at room temperature for 1 hour. The mixture was concentrated and the resulting residue purified by flash chromatography (SiO₂) eluting with dichloromethane/methanol/formic acid (100:5:0.5) to give 37 mg of the title compound.

1H NMR (500 MHz, CD₃ OD (existing as a 1:1 mixture of diastereomers of the hemiacetal)) 7.4-7.25 (m, 5H), 7.0 (d, 2H), 6.65 (d, 2H), 4.65-4.05 (m, 7H), 3.75-3.4 (m, 2H), 3.05-2.3 (m, 5H), 2.2-1.95 (m, 2H), 1.90 (s, 3H), 1.0 (d, 3H), 0.95 (d, 3H).

EXAMPLE 4

We obtained inhibition constants (K_(i)) and IC₅₀ values for several compounds of this invention using enzyme assays with UV-visible substrate and cell assays as described in Example 2. The following K_(i) and IC₅₀ values were determined for compounds 7a, 7b, 20a-d, 21c-f, 22e, 25, 28, 33a-c, 36a, 36b, 39, 43, 47a, 47b, 54a-l, 63, 69a, 69b, 84a and 84b using the indicated assays. Corresponding lettered compound designations are indicated parenthetically. The compound structures are shown in Examples 2 and 5.

    ______________________________________                                                      Assay                                                                                UV-visible                                                                               Cell                                              Compound           K.sub.i (μM)                                                                          IC.sub.50 (μM)                                 ______________________________________                                         7a                 35                                                          7b                 1.2                                                         20a      (= E)     3.2                                                         20b                0.85      16.4                                              20c      (= N)     0.95                                                        20d                0.1       6.2                                               21c                0.64                                                        21d                0.24      4.8                                               21e                0.22      2.9                                               21f                0.17      2.9                                               22e                0.19                                                        25                 6.2                                                         28                 12.0                                                        33a      (= A)     5.5       25.0                                              33b      (= C)     10.0      >30.0                                             33c      (= B)     8.6       20.0                                              36a      (= D)     4.7                                                         36b                0.8       17.0                                              39                 2.5                                                         43                 20.0                                                        47a                0.019     2.1                                               47b                0.027     1.8                                               54a      (= F)     0.15      2.7                                               54b      (= M)     0.15      9.1                                               54c                1.2       >19.0                                             54d                1.0                                                         54e                3.5                                                         54f                0.9                                                         54g      (= G)     4.8       >20.0                                             54h                0.97                                                        54i                0.054     2.4                                               54j                0.28                                                        54k                0.085                                                       54l                0.215     7.0                                               63       (= Q)     0.85      4.1                                               69a      (= R)     0.011     0.735                                             69b      (= S)     0.050     0.745                                             84a      (= V)     0.100     3.3                                               84b      (= W)     0.019     0.50                                              ______________________________________                                    

EXAMPLE 5

Compounds of Example 4 were synthesized as follows: ##STR94##

3-Benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carboxylic acid methyl ester (3). A mixture of (4S)-2-amino-1-pyrroline-5-carboxylic acid ethyl ester hydrochloride (1, 0.44 g, 2.38 mmol; prepared in an analogous fashion as the methyl ester as described by Lee and Lown, J. Org. Chem., 52, 5717-21 (1987)); 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one (2, 0.50 g, 2.31 mmol) and sodium methoxide (0.12 g, 2.22 mmol) in ethanol (10 ml) was refluxed for 2 h. The reaction was allowed to cool to room temperature and concentrated in vacuo. The residue was suspended in water and 1N sulfuric acid was added until pH 1 was reached. The aqueous mixture was extracted with dichloromethane, the organic layer was separated and concentrated in vacuo to yield 0.6 g of a orange solid. Chromatography (flash, SiO₂, 60% ethyl acetate/hexane increased to 100% ethyl acetate stepwise gradient, then 10% methanol/dichloromethane) to give 0.5 g of an orange solid. A mixture of the orange solid and potassium cyanide (0.03 g, 0.5 mmol) in methanol (10 ml) was refluxed overnight. The cooled reaction was concentrated in vacuo to give a yellow solid. Chromatography (flash, SiO₂, 40% ethyl acetate/hexane to 100% ethyl acetate stepwise gradient) afforded 0.22 g (31.6%) of the title compound: ¹ H NMR (d₆ -DMSO) δ 2.25 (m, 1H), 2.65 (m, 1H), 3.15 (m, 2H), 3.75 (s, 3H), 5.15 (dd, 1H), 7.5 (t, 2H), 7.6 (t, 1H), 7.95 (d, 2H), 8.6 (s, 1H), 9.5 (s, 1H).

(3S)-[(3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carbonyl)-amino]-4-oxo-butanoic acid tert-butyl ester semicarbazone (5a and 5b). A mixture of 3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carboxylic acid ethyl ester (3, 0.22 g 0.70 mmol) and lithium hydroxide hydrate (0.032 g, 0.76 mmol) in methanol (5 ml) and tetrahydrofuran (5 ml) and was stirred 18 h at room temperature. The reaction was concentrated to give 3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pryrimidine-6-carboxylic acid lithium salt (4) as a white solid. This was used without further purification in the subsequent reaction.

A 0° C. mixture of (3S)-amino-4-oxo-butanoic acid tert-butyl ester semicarbazone (0.163 g, 0.71 mmol; Graybill et al., Int. J. Protein Res., 44, pp. 173-82 (1994)) and 3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carboxylic acid lithium salt (4) in dimethylformamide (5 ml) and dichloromethane (5 ml) was treated with hydroxybenzotriazole (0.104 g, 0.77 mmol) and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrogen chloride (0.148 g. 0.37 mmol). The reaction was allowed to warm to room temperature and stirred 18 hr. The reaction was poured onto water (50 ml) and extracted with ethyl acetate (2×50 mL). The combined organic layers were washed with aqueous 1M sodium hydrogen sulfate solution, dilute aqueous sodium hydrogen carbonate (50 mL) and saturated aqueous sodium chloride. The organic layer was concentrated in vacuo to yield 0.43 g of a yellow solid. Chromatography (flash, SiO₂, ammonium hydroxide/methanol/dichloromethane (1:1:99 to 1:10:90 stepwise gradient)) gave 0.11 g (30.9%) of the higher Rf diastereomer (5a): ¹ H NMR (CD₃ OD) δ 1.45 (s, 9H), 2.29-2.35 (m, 1H), 2.6-2.7 (m, 2H), 2.8 (dd, 1H), 3.1-3.15 (m, 1H), 3.2-3.3 (m, 1H), 4.9-4.95 (m, 1H), 5.2 (dd, 1H), 7.25 (d, 1H), 7.5-7.55 (m, 2H), 7.55-7.6 (m, 1H), 7.95 (d, 2H), 8.9 (s, 1H) and 0.11 g (30.9%) of the lower Rf diastereomer (5b): ¹ H NMR (CD₃ OD) δ 1.45 (s, 9H), 2.3-2.4 (m, 1H), 2.6-2.7 (m, 1H), 2.7-2.8 (m, 2H), 3.1-3.15 (m, 1H), 3.2-3.3 (m, 1H), 4.85-4.95 (m, 1H), 5.15 (dd, 1H), 7.25 (d, 1H), 7.55 (t, 2H), 7.6 (t, 1H), 7.95 (d, 2H), 8.9 (s, 1H). Diastereomer 5a and diastereomer 5b were taken on separately.

(3S)-[(3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carbonyl)-amino]-4-oxo-butanoic acid (7a). A suspension of (3S)-[(3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carbonyl)-amino]-4-oxo-butanoic acid tert-butyl ester semicarbazone (5a, 0.11 g, 0.22 mmol) in dichloromethane (7.5 ml) and trifluoroacetic acid (2.5 ml) was stirred for 5 h. The reaction was concentrated in vacuo, the residue was taken up in dichloromethane, concentrated in vacuo, suspended in toluene and concentrated in vacuo to give 0.07 g of (3S)-[(3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carbonyl)-amino]-4-oxo-butanoic acid semicarbazone (6a) as a white solid. The solid was suspended in a mixture of 37% aqueous formaldehyde/acetic acid/methanol (1:1:5) and stirred at room temperature for 18 hr. The reaction was concentrated in vacuo, the residue was suspended in acetonitrile and concentrated in vacuo to give 0.1 g of a white solid. Chromatography (HPLC, reverse phase C18, 1% to 75% acetonitrile/water (buffered with 0.1% trifluoroacetic acid) gradient elution) to give 0.05 g (60%) of 7a as a white solid: RT=7.9 min (HPLC, C18 reverse phase, 1 to 100% acetonitrile/water (0.1% trifluoroacetic acid buffer); 20 min gradient elution); ¹ H NMR (CD₃ OD (existing as a 1:1 mixture of anomers of the hemi-acyloxy acetal form)) δ 2.25-2.4 (m, 1H), 2.45-2.8 (m, 4H), 3.05-3.15 (m, 1H), 4.25-4.35 (m, 1H), 4.55-4.6 (m, 1H), 5.1-5.2 (m, 1H), 7.45-7.65 (m, 3H), 7.9-8.0 (m, 2H), 8.9 (s, 1H).

(3S)-[(3-benzoylamino-4-oxo-4,6,7,8-tetrahydro-pyrrolo[1,2-a]pyrimidine-6-carbonyl)-amino]-4-oxo-butanoic acid (7b) was prepared as described for diastereomer 7a to give 0.03 g (35%) of 7b as a white solid: RT=8.1 min (HPLC, C18 reverse phase, 1 to 100% acetonitrile/water (0.1% trifluoroacetic acid buffer); 20 min gradient elution); ¹ H NMR (d₆ -DMSO (existing as a 1:1 mixture of anomers of the hemi-acyloxy acetal form)) δ 2.1-2.2 (m, 1H), 2.4 (d, 1H), 2.7-2.8 (m, 1H), 3.0-3.2 (m, 3H), 5.0 (dd, 1H, 5.1-5.2 (m, 1H), 5.5 (s, 1H), 5.7-5.8 (m, 1H), 7.55 (t, 2H), 7.67 (t, 1H), 7.95 (d, 2H), 8.55 (s, 1H), 9.0-9.15 (m, 1H), 9.4-9.5 (m, 1H). ##STR95## a R=H b R=PhCH₂

c R=Ph(CH₂)₂

d R=Ph(CH₂)₃

e R=4MeO--Ph(CH₂)₃

f R=4HO--Ph(CH₂)₃

Imidazole-2-carboxylic acids 13 were prepared using modifications of described procedures (Yamanaka et al., Chem. Pharm, Bull., 31, pp. 4549-53 (1983)); Suzuki et al., J. Org. Chem., 38, pp. 3571-75 (1973)); and Oliver et al. (J. Org. Chem., 38, pp. 1437-38 (1973)).

Imidazole-2-carboxylic acid (138) was prepared according to Curtis and Brown, J. Org. Chem., 45, pp. 4038-40 (1980).

4-Benzylimidazole-2-carboxylic acid (13b), was isolated as an off-white solid: mp. 153°-155° C.; IR (KBr) 3026-2624, 1630, 1515, 1498, 1438, 1405; ¹ H NMR (d₆ -DMSO) δ 7.31 (5H, m), 7.14 (1H, s), 3.95 (2H, s).

4-(2-Phenylethyl)imidazole-2-carboxylic acid (13c), was isolated as a pale yellow solid: mp. 151°-153° C.; IR (KBr) 3054-2617, 1637, 1497, 1376; ¹ H NMR (d₆ -DMSO) δ 7.27 (5H, m), 7.11 (1H, s), 2.92 (4H, s).

4-(3-Phenylpropyl)imidazole-2-carboxylic acid (13d), was isolated as a pale yellow solid: mp. 148°-150° C.; IR (KBr) 3020-2615, 1636, 1509, 1498, 1383; ¹ H NMR (d₆ -DMSO) δ 7.35-7.22 (5H, m), 7.01 (1H, s), 2.62 (4H, m), 1.94 (2H, m).

4-[3-(4-Methoxyphenyl)propyl]imidazole-2-carboxylic acid (13e), was isolated as a white crystalline solid: mp. 155°-156° C. (decomp.); IR (KBr) 3300-2300, 1633, 1513, 1376, 1244; ¹ H NMR (d₆ -DMSO) δ 9.50-7.50 (2H, bs), 7.15 (1H, s), 7.11 (2H, d, J=8.5), 6.84 (2H, d, J=8.5), 3.71 (3H, s), 2.60-2.50 (4H, m), 1.86 (2H, m). Anal. Calcd for C₁₄ H₁₆ N₂ O₃ : C, 64.60; H, 6.20; N, 10.76. Found: C, 64.45; H, 6.21; N, 10.70.

4-[3-(4-Hydroxyphenyl)propyl]imidazole-2-carboxylic acid (13f). A solution of the ethyl ester of 13e (1.15 g, 4.0 mmol) in dry dichloromethane (50 ml) was treated with boron tribromide (16 ml, 1.0M solution in CH₂ Cl₂, 16.0 mmol) at 0° C. After 15 min at 0° C., the mixture was warmed to 25° C. and stirred for 16 h. The reaction mixture was cooled in an ice bath and quenched with a dropwise addition of water (20 ml). The resulting mixture was briefly stirred at 25° C. then filtered. The filtrate was carefully neutralised by the addition of solid NaHCO₃ to afford 13f (700 mg, 71%) as a white solid: m.p. 186°-187° C. (decomp.) (recrystallised from MeOH); IR (KBr) 3500-2400, 2935, 1640, 1516, 1396, 1232; ¹ H NMR (d₆ -DMSO) δ 9.83 (3H, bs), 7.16 (1H, s), 6.98 (2H, d, J=8.2), 6.66 (2H, d, J=8.2), 2.60-2.40 (4H, m), 1.84 (2H, m). Anal. Calcd for C₁₃ H₁₄ N₂ O₃ : C, 63.40; H, 5.73; N, 11.38. Found: C, 62.96; H, 5.70; N, 11.27.

(2RS, 3S) N² -Tert-butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (14). Tri-n-butyl tin hydride (4.0 ml, 14.9 mmol) was added dropwise to a solution of (2RS, 3S) 3-(N-allyloxycarbonyl) amino-2-benzyloxy-5-oxotetrahydrofuran (Chapman, Biorg. Med. Chem. Lett., 2, pp. 613-18 (1992); (2.91 g, 10 mmol)), N-tert-butoxycarbonyl-L-alanine (2.08 g, 11 mmol) and bis(triphenylphosphine)palladium (II) chloride (150 mg) in dichloromethane (75 ml) until the colour of the solution turned dark orange. Hydroxybenzotriazole (2.70 g, 20 mmol) was added, and the mixture cooled to 0° C. 1-(3-dimethylamino-propyl)-3-ethylcarbodiimide hydrochloride (2.30 g, 12 mmol) was added then the mixture was allowed to warm slowly to room temperature during 4 h. The mixture was diluted with ethyl acetate (250 ml) and washed with 1N hydrochloric acid (3×150 ml), saturated aqueous sodium bicarbonate (3×150 ml) and brine (2×150 ml), then dried (MgSO₄), filtered and concentrated. The crude product was purified by column chromatography (50-70% ethyl acetate/hexane) to afford 3.17 g (84%) of a mixture of diastereomers. Recrystallisation (ethylacetate-hexane) gave colorless crystals: mp. 132°-145° C.; IR (KBr) 3357, 3345, 1781, 1688, 1661, 1535, 1517, 1165; ¹ H NMR (d₆ -DMSO) δ 8.49 (d, J=6.8), 8.23 (d, J=7.4), 7.40 (5H, m), 7.01 (1H, m), 5.68 (d, J=5.0), 4.75 (m), 4.31 (m), 3.97 (1H, m), 2.82 (m), 3.11 (m), 2.82 (m), 2.59 (m), 2.45 (m), 1.40 (9H, s), 1.20 (d, J=7.2), 1.16 (d, J=7.2). Anal. Calcd for C₁₉ H₂₆ N₂ O₆ : C, 60.31; H, 6.92; N, 7.40. Found C, 60.30; H, 6.91; N, 7.38.

(2RS, 3S) tert-Butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (15), was prepared by the method described for 14 to afford 1.64 g (81%) of a colorless glass. IR (KBr) 3317, 2978, 1797, 1697, 1670, 1546, 1400, 1366, 1164, 1121; ¹ H NMR (CDCl₃) δ 7.68 (1H, brm), 7.35 (5H, m); 5.53 (d, J=5.2), 5.43 (s), 4.93-4.61 (m), 4.44 (m), 4.25 (brm), 3.39 (2H, brm), 3.10-2.81 (1H, m), 2.44 (1H, m), 2.32 (brm), 1.88 (brm), 1.67 (brm), 1.42 (9H, s).

(2RS, 3S) N-(N-tert-Butoxycarbonyl-(4(R)-phenoxy-L-prolinyl)-3-amino-2-benzyloxy-5-oxotetrahydrofuran (16) was prepared by the method described for 14 to afford 530 mg (84%) of a colorless amorphous solid: ¹ H NMR (CDCl₃) δ 7.65 (1H, m), 7.4-7.2 (7H, m), 6.95 (1H, m), 6.85 (1H, m), 5.55 (1H, d), 4.95 (1H, d), 4.8-4.7 (1H, brm), 4.65 (1H, d), 4.55-4.45 (1H, brm), 4.4-4.3 (0.5H, brm), 3.95-3.85 (0.5H, brm), 3.75-3.58 (2H, m), 2.95-2.8 (1H, m), 2.7-2.55 (1H, m), 2.54-2.4 (1H, m), 2.35-2.2 (1H, m), 1.4 (9H, s).

(2RS, 3S) N² -[4-(3-Phenylpropyl)imidazole-2-carbonyl]-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (17d). Trifluoroacetic acid (7 ml) was added to a solution of (2RS, 3S) N² -tert-butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (14) (1.00 g, 2.64 mmol) in dichloromethane (7 ml) at 0° C. The mixture was stirred at 0° C. for 75 min. The mixture was concentrated, and the residue treated with diethyl ether then the ether was removed under vacuum. This procedure was repeated twice to yield a pale yellow glass. The solid was dissolved in DMF (20 ml). Diisopropylethylamine (1.38 ml, 7.92 mmol) followed by 4-(3-phenylpropyl) imidazole-2-carboxylic acid (13d) (0.67 g, 290 mmol), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (0.56 g, 2.90 mmol) and hydroxybenzotriazole (0.71 g, 5.28 mmol) were then added to this solution. The mixture was stirred at room temperature for 20 h then poured into brine. The mixture was extracted with ethyl acetate (3×50 ml). The combined organic extracts were washed with saturated aqueous sodium bicarbonate (2×100 ml) then brine (2×100 ml), dried (MgSO₄), filtered and concentrated. The residue was purified by column chromatography (ethyl acetate) to afford 0.99 g (76%) of 17d as a mixture of diastereomers: IR (KBr) 3293, 3064, 2937, 1793, 1650, 1530, 1451, 1446, 1119; ¹ H NMR (CDCl₃) δ 7.96 (brm), 7.62 (brd), 7.36-7.10 (10H, m), 6.88 (s), 6.86 (s), 5.53 (d, J=5.2), 5.48 (s), 4.87-4.52 (4H, m), 3.11-2.38 (2H, m), 2.65 (4H, m), 1.99 (2H, m), 1.47 (d, J=6.9), 1.46 (d, J=7.0).

The following compounds were prepared in a similar manner:

(2RS, 3S) N² -(Imidazole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (17a), was isolated (74%) as a pale yellow solid: IR (KBr) 3289, 3056, 2937, 1793, 1664, 1642, 1528, 1453, 1440, 1124; ¹ H NMR (d₆ -DMSO) δ 13.13 (1H, brs), 8.67 (d, J=7.0), 8.48 (d, J=7.8), 8.29 (d, J=6.8), 8.25 (d, J=7.6), 7.40-7.34 (6H, m), 7.11 (1H, s), 5.69 (d, J=5.9), 5.49 (d, J=0.8), 4.85-4.31 (4H, m), 3.19-2.42 (2H, m), 1.38 (d, J=7.4), 1.34 (d, J=7.4).

(2RS, 3S) N² -(4-Benzylimidazole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (17b), was isolated (75%) as a pale yellow glass: IR (KBr) 3294, 3031, 2937, 1792, 1650, 1530, 1453, 1444, 1119; ¹ H NMR (CDCl₃) δ 7.99 (brm), 7.75 (brd), 7.36-7.11 (10H, m), 6.81 (1H, s), 5.51, 5.45 (d, s, J=5.3), 4.85-4.47 (4H, m), 3.95 (2H, s), 3.04-2.72 (1H, m), 2.48-2.35 (1H, m), 1.44 (d, J=6.9), 1.43 (d, J=7.1).

(2RS, 3S) N² -[4-(2-Phenylethyl)imidazole-2-carbonyl]-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (17c), was isolated (79%) as a pale yellow glass: IR (KBr) 3292, 3029, 2936, 1793, 1650, 1530, 1453, 1444, 1119; ¹ H NMR (CDCl₃) δ 8.06 (brm), 7.70 (brs), 7.39-7.15 (10H, m), 6.82 (s), 6.81 (s), 5.53 (d, J=5.2), 5.48 (s), 4.87-4.53 (4H, m), 2.95 (4H, m), 3.11-2.37 (2H, m), 1.48 (d, J=5.6), 1.45 (d, J=6.7).

(2RS, 3S) 1-[4-(2-Phenylethyl)imidazole-2-carbonyl]-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (18c), was isolated (79%) as a pale yellow glass: IR (CH₂ Cl₂) 3422, 2959, 1795, 1685, 1611, 1497, 1116; ¹ H NMR (d₆ -DMSO) δ 12.78-12.59 (1H, m), 8.61-8.34 (1H, m), 7.39-7.22 (10H, m), 6.99-6.61 (1H, m), 5.71-5.26 (1H, m), 4.85-4.02 (4H, m), 3.63 (1H, m), 3.18-1.74 (11H, m).

(2RS, 3S) 1-[4-(3-Phenylpropyl)imidazole-2-carbonyl]-N-(tetrahydro-2-benzyl-oxy-5-oxo-3-furanyl)-L-prolinamide (18d), was isolated (87%) as a colorless glass: IR (CH₂ Cl₂) 3422, 3214, 2945, 1794, 1685, 1604, 1496, 1117; ¹ H NMR (d₆ -DMSO) δ 12.71 (1H, brm), 8.61-8.34 (1H, m), 7.45-7.18 (10H, m), 7.05-6.64 (1H, m), 5.70-5.28 (1H, m), 4.85-4.02 (4H, m), 3.62 (1H, m) 3.18-1.71 (13H, m).

(2RS, 3S) 1-{4-[3-(4-Methoxyphenyl)propyl]imidazole-2-carbonyl}-N-(tetra-hydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (18e), was isolated (72%) as a white glassy solid: mp. 62°-65° C.; IR (KBr) 3213, 2937, 1793, 1680, 1606, 1606, 1512, 1245; ¹ H NMR (d₆ -DMSO) δ 12.71, 12.67, 12.58 (1H, 3×bs), 8.60-8.30 (1H, m), 7.40-7.20 (5H, m), 7.15-6.55 (5H, m), 5.66-5.20 (1H, m), 4.81-4.59 (2H, m), 4.55-4.05 (2H, m), 3.71 (3H, s), 3.65-3.45 (1H, m), 3.15-1.50 (13H, m). FABSMS m/e 547 (M⁺, 100%), 439, 412, 340, 312, 243, 177, 154.

(2RS, 3S) 1-{4-[3-(4-Hydroxyphenyl)propyl]imidazole-2-carbonyl}-N-(tetra-hydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (18f), was isolated (70%) as a light yellow glassy solid: mp. 86°-90° C.; IR (KBr) 3298, 1790, 1669, 1606, 1515, 1242; ¹ H NMR (d₆ -DMSO) δ 12.66, 12.56 (1H, 2×bs), 9.14 (1H, s), 8.57-8.30 (1H, m), 7.36-7.30 (5H, m), 7.02-6.83 (3H, m), 6.70-6.57 (2H, m), 5.65-5.28 (1H, m), 4.80-4.49 (2H, m), 4.50-4.05 (2H, m), 3.65-3.45 (1H, m), 3.15-1.55 (13H, m). FABMS m/e 533 (M⁺, 100%) 425, 298, 229, 176, 154.

1-{5-[3-(4-Methoxyphenyl)propyl]-1H-imidazole-2-carbonyl}-4(R)-phenoxypyrrolidine-2(S)-carbonyl-(tetrahydro-2(RS)-benzyloxy-5-oxofuran-3(S)-yl)amide (19e) was isolated (77%) as a clear colorless amorphous solid. ¹ H NMR (CDCl₃) δ 9.95-9.75 (1H, m), 7.95 (1H, brs), 7.40-7.2 (7H, m), 7.2-6.78 (7H, m), 5.65-5.6 (1H, m), 5.55-5.45 (1H, m), 5.3-5.2 (1H, m), 5.15-5.0 (1H, m), 4.95-4.75 (1H, m), 4.7-4.6 (1H, m), 4.5-4.4 (1H, m), 4.35-4.25 (1H, m), 3.8 (3H, s), 3.05-1.75 (10H, m).

(3S) 3-{N-[4-(3-Phenylpropyl)imidazole-2-carbonyl]-L-alaninyl}amino-4-oxo-butanoic acid (20d). A mixture of (2RS, 3S) N² -[4-(3-Phenylpropyl)imidazole-2-carbonyl]-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (0.93 g, 1.90 mmol) and 10% palladium on activated carbon (0.93 g) in methanol (100 ml) was stirred under a hydrogen atmosphere for 5 h. The resulting mixture was filtered and concentrated to yield a colorless glass. Recrystallisation from methanol-diethyl ether afforded 401 mg (53%) of 20d as a colorless solid: mp. 94°-96° C.; [α]_(D) ²⁷ +16.4° (c 0.5, MeOH); IR (KBr) 3300, 3287, 1786, 1732, 1659, 1651, 1532, 1451; ¹ H NMR (CD₃ OD) δ 7.19 (5H, m), 6.91 (1H, s), 4.60-4.46 (2H, m), 4.27 (1H, m), 2.63 (4H, m), 2.75-2.40 (2H, m), 1.96 (2H, m), 1.44 (3H, d, J=7.0).

The following compounds were prepared in a similar manner:

(3S) 3-[N-(Imidazole-2-carbonyl)-L-alaninyl]amino-4-oxobutanoic acid (20a; E), was isolated (83%) as a colorless solid: mp. 115° C.; [α]_(D) ²⁵ +4.4° (c 0.5, MeOH); IR (KBr) 3303, 1782, 1658, 1650, 1563, 1521, 1454; 1H NMR (CD₃ OD) δ 7.18 (2H, s), 4.55 (2H, m), 4.27 (1H, m), 2.56 (2H, m), 1.45 (d, J=7.1), 1.44 (d, J=7.0).

(3S) 3-[N-(4-Benzylimidazole-2-carbonyl)-L-alaninyl]amino-4-oxobutanoic acid (20b), was isolated (56%) as a colorless solid: mp. 113°-115° C.; [α]_(D) ²⁹ +18.2° (c 0.5 MeOH). IR (KBr) 3301, 3288, 1783, 1727, 1650, 1531, 1452; ¹ H NMR (CD₃ OD) δ 7.25 (5H, m), 6.90 (1H, s), 4.59-4.45 (2H, m), 4.26 (1H, m), 3.95 (2H, s), 2.74-2.39 (2H, m), 1.42 (3H, d, J=7.0). Anal. Calcd for C₁₈ H₂₀ N₄ O₅ : C, 56.69; H, 5.55; N, 14.69. Found: C, 57.06; H, 5.54; N, 14.41.

(3S) 3-{N-[4-(2-Phenylethyl)imidazole-2-carbonyl]-L-alaninyl}amino-4-oxobutanoic acid (20c; N), was isolated (53%) as a colorless solid: mp. 102°-104° C.; [α]_(D) ²⁷ +13.7° (C 0.5, MeOH); IR (KBr) 3299, 3289, 1785, 1732, 1650, 1531, 1452; ¹ H NMR (CD₃ OD) δ 7.20 (5H, m), 6.82 (1H, s), 4.60-4.46 (2H, m), 4.29 (1H, m), 2.92 (4H, s), 2.76-2.41 (2H, m), 1.44 (3H, 2×d, J=7.1). Anal. Calcd for C₁₉ H₂₂ N₄ O₅ H₂ O: C, 56.43; H, 5.98; N, 13.85. Found: C, 56.65; H, 5.84; N, 13.91.

(3S) 3{N-[4-(2-Phenylethyl)imidazole-2-carbonyl]-L-prolinyl}amino-4-oxobutanoic acid (21c), was isolated (85%) as a colorless glass: mp. 101°-103° C. (methanol-diethyl ether); [α]_(D) ²⁷ -63.8° (C 0.25, MeOH); IR (KBr) 3275, 1784, 1728, 1664, 1606, 1498, 1429; ¹ H NMR (CD₃ OD) δ 7.24 (5H, m), 6.83 (s), 6.79 (s), 4.58-4.14 (3H, m), 3.69 (1H, m), 2.93 (4H, brs), 2.75-1.99 (6H, m). Anal. Calcd for C₂₁ H₂₄ N₄ O₅ H₂ O: C, 58.60; H, 6.09; N, 13.02. Found: C, 58.34; H, 5.96; N, 12.67.

(3S) 3-{N-[4-(3-Phenylpropyl)imidazole-2-carbonyl]-L-prolinyl}amino-4-oxo-butanoic acid (21d), was isolated (81%) as a colorless glass: mp. 91°-94° C.; (methanol-diethyl ether); [α]_(D) ²⁵ -68° (C 0.25, MeOH); IR (KBr) 3277, 2939, 1784, 1727, 1662, 1606, 1498, 1429; ¹ H NMR (CD₃ OD) δ 7.29-7.16 (5H, m), 6.92 (s), 6.86 (s), 4.58-4.16 (3H, m), 3.71 (1H, m), 2.75-1.92 (13H, m). Anal. Calcd for C₂₂ H₂₆ N₄ O₅ H₂ O: C, 59.45; H, 6.35; N, 12.60. Found: C, 59.75; H, 6.21; N, 12.41.

(3S) 3-{N-[4-[3-(4-Methoxyphenyl)propyl]imidazole-2-carbonyl]-L-prolinyl}amino-4-oxobutanoic acid (21e), was isolated (65%) as a white glassy solid: mp. 101°-105° C.; [α]_(D) ²³ -60.6 (c 0.05, MeOH); IR (KBr) 3231, 1784, 1726, 1611, 1512, 1245; ¹ H NMR (CD₃ OD) δ 7.09 (2H, d, J=8.6), 6.92, 6.85 (1H, 2×s), 6.81 (2H, d, J=8.6), 5.45-5.30 (1H, m), 4.64-4.46 (1H, m), 4.28-4.10 (2H, m), 3.75 (3H, s), 3.74-3.66 (1H, m), 2.67-1.84 (13H, m). Anal. Calcd for C₂₃ H₂₈ N₄ O₆ H₂ O: C, 58.22; H, 6.37; N, 11.81. Found: C, 58.39; H, 6.34; N, 11.45; FABMS m/e 457 (M⁺), 405, 312, 243, 215, 176, 154 (100%).

(3S) 3-{N-[4-[3-(4-Hydroxyphenyl)propyl]imidazole-2-carbonyl]-L-prolinyl}amino-4-oxobutanoic acid (21f), was isolated (43%) as a white glassy solid: mp. 114°-118° C.; [α]_(D) ²⁵ -55.7° (c 0.05, MeOH); IR (KBr) 3288, 2935, 1780, 1715, 1662, 1610, 1515, 1441; ¹ H NMR (CD₃ OD) δ 6.99 (2H, d, J=8.5), 6.91, 6.85 (1H, 2×s), 6.68 (2H, d, J=8.5), 5.45-5.30 (1H, m), 4.60-4.47 (1H, m), 4.30-4.10 (2H, m), 3.80-3.55 (1H, m), 2.70-1.80 (13H, m). Anal. Calcd for C₂₂ H₂₆ N₄ O₆ H₂ O: C, 57.38; H, 6.13; N, 12.17. Found: C, 57.68; H, 6.25; N, 11.66. FABMS m/e 443 (M⁺), 298, 229, 154 (100%).

3(S)-[(1-{5-[3-(4-Methoxyphenyl)propyl]-1H-imidazole-2-carbonyl}-4(R)-phenoxy pyrrolidine-2(S)-carbonyl)amino]-4-oxobutanoic acid (22e) was isolated (43%) as a beige solid: ¹ H NMR (CD₃ OD) δ 7.35-7.2 (3H, m), 7.15-7.0 (2H, m), 6.98-6.85 (3H, m), 6.83-6.77 (2H, d), 5.4-5.1 (1H, m), 4.65-4.5 (1H, m), 4.35-4.2 (2H, m), 4.15-3.90 (1H, m), 3.78 (3H, s), 3.62-3.48 (1H, m), 2.78-2.25 (8H, m), 2.02-1.9 (2H, m). ##STR96##

{Phenethyl-[5-(3-propyl)-1H-imidazole-2-carbonyl]amino}acetic acid tert-butyl ester (23). A 0° C. solution of 4-(3-phenylpropyl)-imidazole-2-carboxylic (13d) (150 mg, 0.65 mmol) and N-(2-phenethyl)glycine tert-butyl ester (140 mg, 0.59 mmol) in 5 ml of anhydrous dimethylformamids was treated with diisopropylethylamine (154 μl, 0.89 mmol), hydroxybenzotriazole (160 mg, 1.18 mmol), and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (136 mg, 0.71 mmol). After stirring for 36 h, the reaction was poured onto saturated aqueous sodium chloride and extracted with ethyl acetate (3×50 ml) The combined organic extracts were washed twice with saturated aqueous sodium bicarbonate (2×) and saturated aqueous sodium chloride (1×), dried (Na₂ SO₄), filtered, and concentrated in vacuo to give a brown oil. Chromatography (flash, SiO₂, 30% ethyl acetate/hexane) to give 160 mg (61%) of 23 as a white solid: ¹ H NMR (CDCl₃) δ 7.38-7.14 (10H, m), 6.85-6.8 (1H, m), 4.84-4.76 (1H, d), 4.5-4.42 (1H, m), 4.07-4.0 (1H, d), 3.78-3.72 (1H, m), 3.12-2.94 (2H, 2×m), 2.75-2.55 (4H, m), 2.1-1.95 (2H, m), 1.5-1.45 (9H, 3×s).

(3S)-(2-Phenethyl-[5-(3-phenylpropyl)-1H-imidazole-2-carbonyl]amino}acetyl amino) 4-oxobutanoic acid tert-butyl ester semicarbazone (24). The ester 23 (160 mg, 0.357 mmol) was treated with 25% trifluoroacetic acid/dichloromethane (7 ml) for 4 h. The reaction was concentrated in vacuo to afford 180 mg of the acid. The acid (180 mg, 0.357 mmol) was coupled to (3S)-3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone (161 mg, 0.357 mmol) as describe for the preparation of 5a and 5b to give 86 mg (33%) of 24 (one diastereomer) as a white solid: ¹ H NMR (CDCl₃) δ 10.9-10.3 (1H, 2d), 10.08-9.78 (1H, 2d), 9.25-9.15 (1H, m), 8.35-8.10 (1H, 2m), 7.9-7.85 (1H, 2 s), 7.40-7.05 (10H, m), 6.9-6.75 (1H, m), 6.3-5.8 (1H, br s), 5.2-4.65 (2H, m), 4.35-3.5 (3H, m), 3.25-3.0 (2H, m), 2.9-2.45 (6H, m), 2.05-1.8 (2H, m), 1.4 (9H, s).

(3S)-(2-{Phenethyl-[5-(3-phenylpropyl)-1H-imidazole-2-carbonyl]amino}acetylamino)-4-oxobutanoic acid trifluoroacetic acid salt (25) was prepared by the method described for 7a to afford 32 mg (82%) as a white solid: ¹ H NMR (CD₃ OD) δ 7.05-7.35 (m, 11H), 4.65 (m, 1H), 4.4 (m, 1H), 4.3 (s, 2H), 3.6-4.0 (m, 2H), 2.5-2.95 (m, 8H), 2.05 (m, 2H).

7-[5-(3-Phenylpropyl)-1H-imidazole-2-carbonyl]-1,4-dithia-7-azaspiro[4.4]nonane-8(S)-carboxylic acid methyl ester (26). 4-(3-Phenylpropyl)imidazole-2-carboxylic acid (13d) was coupled to 1,4-dithia-7-azaspiro[4.4]nonane-8(S)-carboxylic acid methyl ester hydrobromide (Smith et. al., J. Med. Chem., 31, pp. 875-85 (1988)) by the method described for 23 to afford 140 mg (65%) as a yellow gum: ¹ H NMR (CDCl₃) δ 7.34-7.15 (5H, m), 6.98-6.8 (1H, 3 s), 5.7-5.65 (0.5H, m), 5.2-5.1 (1H, m), 4.82-4.75 (0.5H, m), 4.4-4.35 (1H, m), 4.05 (1H, d), 3.75-3.7 (3H, 2 s), 3.4-3.3 (4H, m), 2.95-2.45 (8H, m), 2.05-1.95 (2H, m).

(3S)-({7-[5-(3-Phenylpropyl)-1H-imidazole-2-carbonyl]-1,4-dithia-7-azaspiro[4.4]nonane-8(S)-carbonyl}-amino)-4-oxobutanoic acid tert-butyl ester semicarbazone (27). Following the procedure described for 4, the ester 26 was converted to its acid which was subsequently coupled to (3S)-3-amino-4-oxobutanoic acid tert-butyl ester semicarbazone as described for 24 to give 70 mg (33%) as a brown solid: ¹ H NMR (CD₃ OD) δ 7.28-7.10 (5H, m), 6.90 (1H, br s), 4.94 (1H, m), 3.96-3.86 (2H, q), 3.35-3.25 (4H, d), 3.0 (2H, s), 2.73-2.59 (6H, m), 2.0-1.92 (2H, m),1.44 (9H, s).

(3S)-({7-[5-(3-Phenylpropyl)-1H-imidazole-2-carbonyl]-1,4-dithia-7-azaspiro[4.4]nonane-8(S)-carbonyl}-amino)-4-oxobutanoic acid (28) was prepared by the method described for 7a to afford 17 mg (26%) as a light brown solid: ¹ H NMR (CD₃ OD) δ 7.4 (s, 1H), 7.1-7.25 (m, 5H), 4.9 (m, 1H), 4.6 (m, 1H), 4.3 (m, 1H), 3.95 (s, 2H), 3.25-3.4 (m, 4H), 3.0 (d, 2H), 2.6-2.8 (m, 5H), 2.45 (m, 1H), 2.05 (m, 2H). ##STR97## a R=Ph(CH₂)₂ b R= 4CF₃ --Ph(CH₂)₂

c R=PhCH₂

4,5-Dihydroimidazole-4-carboxylic esters (29) were prepared by a modification of the procedure described by Jones et al., Tetrahedron Lett., 29, pp. 3853-56 (1988).

(4RS) Methyl 2-(2-phenylethyl)-4,5-dihydroimidazole-4-carboxylate (29a). Dry hydrogen chloride was bubbled into a solution of hydrocinnamonitrile (3.28 ml, 25 mmol) in methanol (125 ml) at 0° C. for 45 mins. The solvents were removed to give the imidate salt which was dissolved in methanol (125 ml) along with methyl 2,3-diaminopropionate (25 mmol) (Jones et al., supra). The mixture was kept at room temperature for 2.5 h, then concentrated to a yellow oil. The crude product was purified by column chromatography (10-20% methanol/dichloromethane) to afford 3.52 g (61%) of a colorless glass: ¹ H NMR (CDCl₃) δ 7.30-7.15 (5H, m), 4.63 (1H, t, J=9.7), 3.96 (2H, d, J=9.7), 3.72 (3H, s), 3.10 (4H, m), ¹³ C NMR (CDCl₃) δ 171.3, 168.8, 138.3, 128.4, 128.2, 126.6, 57.3, 53.0, 47.7, 31.7, 27.9.

(4RS) Methyl 2-[2-(4-trifluoromethylphenyl)ethyl]-4,5-dihydroimidazole-4-carboxylate (29b), was prepared by the method described for 29a to yield 6.80 g (78%) of a colorless solid: mp. 136°-141° C.; ¹ H NMR (CDCl₃) δ 7.45 (4H, s), 4.71 (1H, dd, J=8.6, 10.8), 4.02 (2H, m), 3.73 (3H, s), 3.19 (4H, m).

Imidazole-4-carboxylic esters 30 were prepared by a modification of the procedure described by Martin et al., J. Org. Chem., 33, pp. 3758-61 (1968).

Methyl 2-(2-phenylethyl)imidazole-4-carboxylate (30a). A mixture of (4RS) methyl 2-(2-phenylethyl)-4,5-dihydroimidazole-4-carboxylate (29a) (3.40 g, 14.64 mmol), chloroform (75 ml) and manganese (IV) oxide (13.0 g, 150 mmol) was heated under reflux for 21 h then filtered hot. The solids were washed with chloroform and methanol. The combined filtrates were concentrated to leave a yellow-brown solid, which was purified by column chromatography (2-5% methanol/dichloromethane) to afford 1.46 g (43%) of a pale yellow solid: mp. 151°-155° C.; IR (KBr) 3028, 2946, 1720, 1533, 1433, 1348, 1195, 1166; ¹ H NMR (CDCl₃) δ 7.62 (1H, s), 7.26-7.02 (5H, m), 3.82 (3H, s), 3.03 (4H, brs), ¹³ C NMR (CDCl₃) δ 62.9, 150.2, 140.3, 128.5, 128.2, 126.3, 51.5, 34.5, 30.4. Anal. Calcd for C₁₃ H₁₄ N₂ O₂ : C, 67.81; H, 6.13; N, 2.16. Found: C, 67.70; H, 6.15; N, 12.16.

Methyl 2-[2-(4-trifluoromethylphenyl)ethyl]imidazole-4-carboxylate (30b), was prepared by the method described for 30a. It was recrystallised from ethyl acetate to afford 1.88 g (33%) of cream Crystals: mp. 225°-26° C.; IR (KBr) 3239, 2951, 1715, 1532, 1331, 1158, 1105, 1068; ¹ H NMR (CDCl₃) δ 7.61 (1H, s), 7.54 (2H, d, J=8.1), 7.26 (2H, d, J=8.1), 3.89 (3H, s), 3.10 (4H, m). Anal. Calcd for C₁₄ H₁₃ F₃ N₂ O₂ : C, 56.38; H, 4.39; N, 9.39; F, 19.11. Found: C, 56.23; H, 4.44; N, 9.33; F, 19.08.

2-(2-Phenylethyl)imidazole-4-carboxylic acid (31a). A mixture of methyl 2-(2-phenylethyl)imidazole-4-carboxylate (30a) (1.38 g, 6 mmol), methanol (30 ml) and 1M aqueous sodium hydroxide (30 ml) was heated under reflux for 16 h. The methanol was removed under reduced pressure, and the resulting aqueous solution was neutralised with 4M hydrochloric acid, whereupon a pale yellow solid precipitated. The precipitate was collected, washed with water, and dried to afford 1.18 g (91%) of a pale yellow solid: mp. 117°-120° C.; IR (KBr) 3375, 3131, 2616, 2472, 1638, 1592, 1551, 1421, 1388, 1360; ¹ H NMR (d₆ -DMSO) δ 7.59 (1H, s), 7.26 (5H, m), 2.99 (4H, m). Anal. Calcd for C₁₂ H₁₂ N₂ O₂ 0.25H₂ O: C, 65.29; H, 5.71; N, 12.69. Found: C, 65.00; H, 5.64; N, 12.58.

2-[2-(4-Trifluoromethylphenyl)ethyl]imidazole-4-carboxylic acid (31b), was prepared by the method described for 31a to afford 1.09 g (76%) of a pale yellow solid: mp. 126°-130° C.; IR (KBr) 3339, 2640-2467, 1638, 1589, 1545, 1383, 1323; ¹ H NMR (d₆ -DMSO) δ 7.69 (2H, d, J=8.0), 7.59 (1H, s), 7.47 (2H, d, J=8.0), 3.06 (4H, m).

(2RS, 3S) N² -[2-(2-Phenylethyl)imidazole-4-carbonyl]-N-(tetrahydro-2-benzyl-oxy-5-oxo-3-furanyl)-L-alaninamide (32a). To a solution of (2RS, 3S) N² -tert-butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (14) (1.59 g, 4.20 mmol; Chapman, Biorg. Med. Chem. Lett., 2, pp. 613-18 (1992)) in dichloromethane (15 ml), cooled to 0° C., was added trifluoroacetic acid (15 ml). The mixture was stirred at 0° C. for 1 h and then concentrated. The residue was treated with ether and then the ether was removed under vacuum. This procedure was repeated twice to yield a pale yellow glass. The solid was dissolved in DMF (20 ml), then diisopropylethylamine (2.19 ml, 12.6 mmol), 2-(2-phenylethyl)imidazole-4-carboxylic acid (31a) (1.0 g, 4.62 mmol), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (0.89 g, 4.62 mmol) and hydroxybenzotriazole (1.14 g, 8.40 mmol) were added to the solution. The reaction mixture was stirred at room temperature for 20 h then poured into brine. The mixture was extracted with ethyl acetate (3×50 ml). The combined organic extracts were washed with saturated aqueous sodium bicarbonate (3×100 ml) then brine (3×100 ml), dried (MgSO₄) and concentrated. The residue was purified by column chromatography (2-10% isopropanol in dichloromethane then 0-6% isopropanol in ethyl acetate) to yield 1.10 g (55%) of 32a as a mixture of diastereomers: IR (KBr) 3278, 3065, 1790, 1641, 1577, 1545, 1499, 1454, 1120; ¹ H NMR (CDCl₃) δ 10.26 (1H, s), 8.14 (1H, s), 7.66 (d, J=7.0), 7.56 (d, J=7.0), 7.43 (1H, s), 7.31-7.11 (10H, m), 5.49 (d, J=5.6), 5.48 (s), 4.83-4.41 (4H, m), 3.04-2.41 (2H, m), 2.99 (4H, s), 1.45 (d, J=7.0), 1.44 (d, J=7.0).

(2RS, 3S) N² -{2-[2-(4-Trifluoromethylphenyl)ethyl]imidazole-4-carbonyl}-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (32b), was prepared by the method described for 32a to afford 1.08 g (62%) of a pale yellow glass: IR (KBr) 3376, 3284, 3070, 2938, 1791, 1642, 1578, 1546, 1327, 1165, 1122, 1068; ¹ H NMR (CDCl₃) δ 7.95 (0.5H, m), 7.55-7.25 (11.5H, m), 5.53 (s), 5.49 (d, J=5.3), 4.88-4.48 (4H, m), 3.11-2.96 (4H, m), 2.91 (1H, m), 2.51 (1H, m), 1.47 (3H, d, J=7.1).

(2RS, 3S) N² -(2-Benzylimidazole-4-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (32c), was prepared by the method described for 32a from 2-benzylimidazole-4-carboxylic acid (Ger. Offen. DE 3427136) to afford 1.139 (83%) of a yellow glass: IR (CH₂ Cl₂) 3433, 3062, 2990, 1803, 1693, 1584, 1504, 1429, 1285, 1258; ¹ H NMR (CDCl₃) δ 9.50 (s), 9.37 (s), 7.86 (0.5H, d, J=6.1), 7.56-7.21 (10.5H, m), 7.48 (1H, s), 5.51 (d, J=5.2), 5.48 (s), 4.87-4.41 (4H, m), 4.08 (s), 4.07 (s), 3.03-2.39 (2H, m), 1.46 (3H, d, J=7.0).

(3S) 3-{N-[2-(2-Phenylethyl)imidazole-4-carbonyl]-L-alaninyl}amino-4-oxobutanoic acid (33a; A). A mixture of (2RS, 3S) N² -[2-(2-phenylethyl)imidazole-4-carbonyl]-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (32a) (1.0 g, 2.10 mmol) and 10% palladium on activated carbon (1.0 g) in methanol (50 ml) was stirred under a hydrogen atmosphere for 4.5 h. The resulting mixture was filtered and concentrated to yield a colorless glass. Recrystallisation from methanol-diethyl ether afforded 510 mg (63%) of a colorless solid: mp. 127° C.; IR (KBr) 3360, 3279, 2981, 1781, 1732, 1646, 1577, 1547; ¹ H NMR (CD₃ OD) δ 7.54 (1H, s), 7.29-7.12 (5H, m), 4.60-4.47 (2H, m), 4.28 (1H, m), 3.01 (4H, s), 2.76-2.39 (2H, m), 1.43 (3H, 2×d, J=7.0, J=7.0), ¹³ C NMR (CD₃ OD) δ 176.2, 176.0, 174.7, 174.6, 164.4, 164.3, 150.5, 141.9, 134.8, 129.5, 129.3, 127.3, 122.3, 98.8, 98.4, 52.3, 52.0, 50.3, 35.6, 31.2, 18.8, 18.7. Anal. Calcd for C₁₉ H₂₂ N₄ O₅ H₂ O: C, 56.43; H, 5.98; N, 13.85. Found: C, 56.78; H, 5.70; N, 13.77.

(3S) 3-{N-[2-(2-[4-Trifluoromethylphenyl]ethyl)imidazole-4-carbonyl]-L-alaninyl}-amino-4-oxobutanoic acid (33b; C), was prepared by the method described for 33a to afford 612 mg (73%) of a colorless solid: mp. 120°-124° C.; [α]_(D) ²³ +14.3° (C 0.5, MeOH); IR (KBr) 3287, 2985, 2937, 1782, 1732, 1646, 1579, 1547, 1327; ¹ H NMR (CD₃ OD) δ 7.56 (2H, d, J=8.0), 7.54 (1H, s), 7.36 (2H, d, J=8.0), 4.60-4.48 (2H, m), 4.28 (1H, m), 3.08 (4H, m), 2.75-2.41 (2H, m), 1.43 (3H, d, J=7.0). Anal. Calcd for C₂₀ H₂₁ F₃ N₄ O₅. 0.5H₂ O: C, 51.84; H, 4.78; N, 12.09; F, 12.30. Found: C, 51.83; H, 4.72; N, 12.14; F, 12.36.

(3S) 3-[N-(2-Benzylimidazole-4-carbonyl)-L-alaninyl]amino-4-oxobutanoic acid (33c; B), was prepared by the method described for 33a to afford 426 mg (64%) of a colorless solid: [α]_(D) ²³ +13.4° (c 0.407, MeOH). IR (KBr) 3260, 3150, 2980, 1779, 1727, 1649, 1573, 1547; ¹ H NMR (CD₃ OD) δ 7.58 (1H, s), 7.34-7.22 (5H, m), 4.59-4.47 (2H, m), 4.28 (1H, m), 4.07 (2H, s), 2.74-2.41 (2H, m), 1.42 (3H, d, J=6.7); ¹³ C NMR (CD₃ OD) δ 175.6, 175.5, 175.0, 164.6, 164.5, 150.1, 138.7, 135.3, 130.0, 129.9, 128.2, 122.9, 98.9, 98.5, 52.5, 52.2, 35.5, 35.1, 35.0, 19.0, 18.9. Anal. Calcd for C₁₈ H₂₀ N₄ O₅ H₂ O: C, 55.37; H, 5.68; N, 14.35. Found C, 55.83; H, 5.75; N, 13.96. MS (FAB, m/z): 373 ((M⁺), 228, 185, 91. ##STR98## (a) R=H (b) R=CH₂ Ph

5-Benzylpyrrole-2-carboxylic acid (34b). A mixture of Ethyl 5-benzylpyrrole-2-carboxylate (0.7 g, 3.05 mmol; Elder et al., Synthetic Communications, 19, 763-767 (1989)), ethanol (20 ml) and 1M sodium hydroxide (9.2 ml, 9.2 mmol) was stirred and heated under reflux for 3 h. The major part of the ethanol was removed and the remaining liquid was diluted with water, washed with ether, cooled in ice and acidified with concentrated hydrochloric acid. The mixture was extracted with ether. The combined extracts were washed with brine, dried (Na₂ SO₄) and concentrated to afford 0.567 g (92%) of an off white solid: mp. 130°-134° C.; ¹ H NMR (CDCl₃) δ 8.87 (1H, brs), 7.37-6.95 (5H, m), 6.97 (1H, m), 6.07 (1H, m), 4.00 (2H, s).

(2RS, 3S) N² -(Pyrrole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (35a). A solution of (2RS, 3S) N² -tert-butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (14) (756 mg, 2.0 mmol) in dry dichloromethane (8 ml) at 0° C. was treated with trifluoroacetic acid (8 ml) for 1 h and then evaporated to dryness. Dry ether was added to the residue and the mixture concentrated to give a viscous oil. The oil was dissolved in dry DMF (10 ml).

Pyrrole-2-carboxylic acid (34a) (244 mg, 2.2 mmol) was added and the solution was cooled in an ice bath before the addition of N,N-diisopropylamine (0.78 g, 6.0 mmol), 1-hydroxybenzotriazole (0.54 g, 4.0 mmol) and ethyl dimethylaminopropyl carbodiimide hydrochloride (0.42 g, 2.2 mmol). The resulting mixture was stirred at 25° C. for 17 h and then saturated aqueous sodium chloride (30 ml) was added. The mixture was extracted with ethyl acetate (3×20 ml) and the combined organic extracts were washed with 5% aqueous sodium bicarbonate (3×10 ml) and brine (10 ml), dried (MgSO₄) and concentrated. Flash chromatography (25% hexane-ethyl acetate) afforded 557 mg (75%) of a 1:1 mixture of diastereomers as a white glassy solid: mp. 85°-90° C.; IR (KBr) 3288, 1789, 1665, 1629, 1557 and 1122; ¹ H NMR (d₆ -DMSO) δ 11.46 (1H, bs), 8.55 (0.5H, d, J=7.0), 8.30 (0.5H, d, J=7.6), 8.06 (0.5H, d, J=7.0), 8.04 (0.5H, d, J=7.6), 7.36-7.30 (5H, m), 6.88-6.85 (2H, m), 6.10-6.07 (1H, m), 5.63 (0.5H, d, J=5.0), 5.42 (0.5H, s), 4.72 (2H, q, J=12.2), 4.74-4.25 (2H, m), 3.14-2.35 (2H, m), 1.29, 1.25 (3H, 2×d, J=7.2).

(2RS, 3S) N² -(5-Benzylpyrrole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-alaninamide (35b), was prepared from 5-benzylpyrrole-2-carboxylic acid (34b) by the method described for compound 35a (65%). Data is given for a single diastereomer. ¹ H NMR (d₆ -DMSO) δ 11.37 (1H, brs,), 8.27 (1H, d, J=7.4), 7.93 (1H, d, J=7.6), 7.33-7.16 (10H, m), 6.76 (1H, m), 5.82 (1H, m), 5.62 (1H, d, J=5.2), 4.76 (1H, d, J=12.0), 4.65 (1H, m), 4.62 (1H, d, J=12.2), 4.47 (1H, m), 3.88 (2H, s), 2.77 (1H, dd, J=9.0, 18.0), 2.5 (dd), 1.23 (3H, d, J=7.0).

(3S) 3-[N-(Pyrrole-2-carbonyl)-L-alaninyl]amino-4-oxobutanoic acid (36a; D). A mixture of (35a) (612 mg; 1.65 mmol), methanol (40 ml) and 10% palladium on carbon (500 mg) was vigorously stirred under an atmosphere of hydrogen for 4 h. The mixture was filtered through a 0.2 μM nylon membrane then concentrated. The residue was purified by flash chromatography (5-10% methanol in methylene chloride) to afford the hemihydrate of (36a) (223 mg, 48%) as a white solid after precipitation from an ethyl acetate-ether mixture. There were traces of solvent in the product: mp. 96°-100° C.; IR (KBr) 3381, 1774, 1729 (EtOAc), 1632, 1558, 1523, 1123; ¹ H NMR (CD₃ OD) δ 6.94-6.85 (2H, m), 6.17 (1H, dd, J=3.8 and 2.6), 4.58 (0.5H, d, J=3.94), 4.56 (0.5H, d, J=4.24), 4.51 (1H, q, J=7.16), 4.35-4.20 (1H, m), 2.74-2.40 (2H, m), 1.42 and 1.41 (3H, 2×d, J=7.13).

(3S) 3-[N-(5-Benzylpyrrole-2-carbonyl)-L-alaninyl]amino-4-oxobutanoic acid (36b), was prepared (41%) from 35b by the method described for compound 36a, to afford an off white solid: mp. 109°-112° C.; [α]_(D) ²⁵ +6.3° (c 0.3, methanol); IR (KBr) 3368, 1724, 1630, 1530, 1453, 1414, 1233, 1049; ¹ H NMR (d₄ methanol) δ 7.25-7.11 (5H, m), 6.76 (1H, d, J=3.5), 5.84 (1H, d, J=3.5), 4.51 (1H, m), 4.43 (1H, q, J=7.1), 4.23 (1H, m), 2.5 (2H, m), 1.35 (3H, d, J=7.0). Anal. Calcd for C₁₉ H₂₁ N₃ O₅ . 1.75H₂ O: C, 56.64; H, 6.13; N, 10.43. Found: C, 56.34; H, 5.72; N, 10.00. ##STR99##

(2RS, 3S) 1-(Indole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (38). Trifluoroacetic acid (4 ml) was added to a solution of (2RS, 3S) 1-tert-butoxycarbonyl-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (15) (0.607 g, 1.5 mmol) in dichloromethane (4 ml) at 0° C. The mixture was stirred at 0° C. for 75 min. The mixture was concentrated, and the residue treated with diethyl ether, then the ether was removed under vacuum. This procedure was repeated twice to yield a yellow oil, which was dissolved in DMF (12 ml). Diisopropyl-ethylamine (0.78 ml, 4.5 mmol) followed by indole-2-carboxylic acid (266 mg, 1.65 mmol), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (316 mg, 1.65 mmol) and hydroxybenzotriazole (405 mg, 3 mmol) were then added to the solution. The mixture was stirred at room temperature for 20 h then poured into brine. The mixture was extracted with ethyl acetate (3×30 ml). The combined organic extracts were washed with saturated aqueous sodium bicarbonate (2×60 ml) then brine (2×60 ml), dried (MgSO₄), filtered and concentrated. The residue was purified by column chromatography (ethyl acetate) to afford 518 mg (77%) of a mixture of diastereomers: IR (KBr) 3314, 1780, 1677, 1609, 1524, 1435, 1406, 1344; ¹ H NMR (d₆ -DMSO), δ 11.58 (1H, m), 8.81-8.41 (1H, m), 7.71-6.67 (10H, m), 5.70 (d, J=5.2), 5.48 (s), 4.89-4.29 (4H, m), 3.99-3.74 (2H, m), 3.20-2.44 (2H, m), 2.39-1.77 (4H, m).

(3S) 3-[1-(Indole-2-carbonyl)-L-prolinyl]amino-4-oxobutanoic acid (39). A mixture of (2RS, 3S) 1-(indole-2-carbonyl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)-L-prolinamide (38) (478 mg, 1.07 mmol) and 10% palladium on carbon (475 mg) and methanol (150 ml) was stirred under a hydrogen atmosphere for 6 h. The resulting mixture was filtered and concentrated to yield a colorless glass. Recrystallisation from a mixture of methanol and diethyl ether afforded 202 mg (53%) of a colorless solid: mp. 135°-138° C.; [α]_(D) ²⁴ -44° (c 0.25, CH₃ OH); IR (KBr) 3287, 2977, 2879, 1781, 1725, 1716, 1667, 1662, 1600, 1529, 1441, 1346; ¹ H NMR (CD₃ OD) δ 7.65 (1H, d, J=8.0), 7.44 (1H, d, J=8.4), 7.22 (1H, m), 7.09-6.84 (2H, m), 4.62 (2H, m), 4.29 (1H, m), 4.15-3.73 (2H, m), 2.74-1.72 (6H, m). ##STR100##

Methyl 2-(3,5-dihydro-7-methyl-4-oxo-4H-pyrrolo[3,2-d]pyrimidin-3-yl)acetate (40). Freshly prepared methyl glycinate (1.25 g, 14 mmol) was added to a stirred solution of ethyl 3-[N-(dimethylamino)methylene]amino-4-methylpyrrole-2-carboxylate (1.56 g, 7.0 mmol; Lim et al., J. Org. Chem., 44, pp. 3826-29 (1979)) in dry methanol (60 ml). The resulting mixture was kept at 70° C. Two further batches of methyl glycinate (1.25, 14.0 mmol) were added after 18 h and 42 h heating. The mixture was cooled and filtered 24 h after the final addition. The filtrate was concentrated and the residue purified by flash chromatography (2-5% methanol/chloroform) to afford 0.54 g (35%) of a white crystalline solid: mp. 233°-235° C. (recrystallised from ethyl acetate); IR (KBr) 3135, 2958, 1745, 1675, 1254; ¹ H NMR (d₆ -DMSO) δ 11.90 (1H, s), 8.07 (1H, s), 7.23 (1H, s), 4.83 (2H, s), 3.69 (3H, s), 2.16 (3H, s). Anal. Calcd for C₁₀ H₁₁ N₃ O₃ 0.1H₂ O: C, 53.85; H, 5.07; N, 18.84. Found: C, 53.85; H, 4.96; N, 18.81; MS (70eVE.I.) m/e 222, 221 (M⁺, 100%), 189, 162, 133, 105.

2-(3,5-Dihydro-7-methyl -4-oxo-4H-pyrrolo[3,2-d]pyrimidin-3-yl)acetic acid, sodium salt (41). A suspension of 40 (354 mg, 1.6 mmol) in methanol (15 ml) was treated with 0.5N sodium hydroxide (4.8 ml) and the resulting mixture was stirred at 25° C. for 1 h. The reaction mixture was filtered to afford the hemihydrate of 41 (354 mg, 97%) as a white crystalline solid: mp. >340° C. (recrystallised from methanol); IR (KBr) 3461, 3143, 1676, 1666, 1605, 1415; ¹ H NMR (d₆ DMSO) δ 11.63 (1H, s), 7.83 (1H, s), 7.11 (1H, d, J=2.0), 4.24 (2H, s), 2.14 (3H, s). Anal. Calcd for C₉ H₈ N₃ O₃ Na. 0.5H₂ O: C, 45.39; H, 3.81; N, 17.64. Found: C, 45.57; H, 4.05; N, 17.39.

(2RS, 3S) 2-(3,5-Dihydro-7-methyl-4-oxo-4H-pyrrolo[3,2-d]pyrimidin-3-yl)-N-(tetrahydro-2-benzyloxy-5-oxo-3-furanyl)acetamide (42). A suspension of the sodium salt 41 (344 mg, 1.5 mmol) in dry DMF (15 ml) was treated with ethyl dimethylaminopropyl carbodiimide hydrochloride (373 mg, 1.95 mmol) and 1-hydroxybenzo-triazole (405 mg, 3.0 mmol). The mixture was kept at 25° C. for 1 h then (2RS, 3S) N-allyloxycarbonyl-3-amino-2-benzyloxy-5-oxotetrahydrofuran (437 mg, 1.5 mmol; Chapman, Biorg. Med. Chem. Lett., 2, pp. 613-18 (1992)) and (Ph₃ P)₂ PdCl₂ (25 mg) were added followed by the dropwise addition of n-tributyltin hydride (0.6 ml, 2.25 mmol). The resulting mixture was stirred at 25° C. for 1 h then water (20 ml) was added. The mixture was extracted with ethyl acetate (3×15 ml), and the combined organic extracts were washed with water (5 ml), dried (MgSO₄), and concentrated to afford a mixture of diastereomers. Evaporation of the aqueous phase and purification of the residue by flash chromatography (5% methanol/chloroform) gave an additional quantity affording a total 182 mg of 42 (31%): m.p. 240°-244° C.; IR (KBr) 3274, 1772, 1691, 1664, 1562; ¹ H NMR (d₆ -DMSO) δ 11.81 (1H, s), 8.85 (0.6H, d, J=6.6), 8.72 (0.4H, d, J=7.4), 7.98 (0.6H, s), 7.95 (0.4H, s), 7.40-7.30 (5H, m), 7.20 (1H, d, J=2.2), 5.61 (0.4H, d, J=5.0), 5.46 (s), 4.85-4.60 (m), 4.28 (m), 3.20-2.35 (2H, m), 2.16 (3H, s).

(3S)-3-[2-(3,5-Dihydro-7-methyl-4-oxo-4H-pyrrolo[3,2-d]pyrimidin-3-yl)-1-oxo-ethylamino]-4-oxobutanoic acid (43). A mixture of 42 (131 mg, 0.33 mmol), in methanol (50 ml) and 10% palladium on carbon (100 mg) was stirred vigorously under an atmosphere of hydrogen for 2 h. An additional quantity of catalyst (100 mg) was added and the mixture hydrogenated for a further 2 h. The mixture was filtered through a 0.2 μM nylon membrane, and concentrated. The residue was recrystallised from methanol/diethyl ether to afford 79 mg (78%) of 43 as a hygroscopic white solid: mp. 222°-226° C.; (decomp.); [α]_(D) ³² +0.5 (c 0.02, MeOH); IR (KBr) 3282, 1680, 1558, 1425 1275; ¹ H NMR (CD₃ OD) δ 8.03 (1H, s), 7.18 (1H, d, J=0.7), 4.79-4.74 (2H, m), 4.63-4.59 (1H, 2×d, J=3.6), 4.36-4.25 (1H, m), 2.78-2.39 (2H, m), 2.24 (3H, d, J=0.7). Anal. Calcd for C₁₃ H₁₄ N₄ O₅. 1.4H₂ O: C, 47.10; H, 5.12; N, 16.90. Found: C, 47.00; H, 4.79; N, 16.59. FABMS m/e 307, 306 (M⁺), 244, 207, 190, 152, 115 (100%). ##STR101##

(1S, 9S) t-Butyl 6,10-dioxo-octahydro-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylate (44a). To a solution of (1S, 9S) t-butyl 9-amino-6,10-dioxo-octahydro-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylate (690 mg; 2.32 mmol; GB 2128984) in dioxane (16 ml) and water (4 ml) at 0° C. was added solid sodium bicarbonate (292 mg; 3.48 mmol) followed by dropwise addition of 3-phenylpropionyl chloride (470 mg; 2.78 mmol). The mixture was stirred at room temperature for 2 h then more sodium bicarbonate (200 mg; 2.38 mmol) and 3-phenylpropionyl chloride (100 mg; 0.6 mmol) was added. The mixture was stirred for a further 2 h at room temperature, diluted with ethyl acetate (50 ml), washed with saturated sodium bicarbonate (2×25 ml) then dried (MgSO₄) and concentrated. The residue was purified by flash chromatography (0-50% ethyl acetate/chloroform) and finally crystallised by trituration with ether to afford 860 mg (86%) of a white solid: mp. 137°-138° C.; [α]_(D) ²³ -95.1° (c 0.549, CH₂ Cl₂); IR (KBr) 3327, 1736, 1677, 1664, 1536, 1422, 1156; ¹ H NMR (CDCl₃) δ 7.24 (5H, m), 6.50 (1H, d, J=7.5), 5.24 (1H, m), 4.90 (1H, m), 4.60 (1H, m), 3.44 (1H, m), 2.93 (2H, m), 2.84 (1H, m), 2.64 (1H, m), 2.54 (2H, m), 2.26 (2H, m), 1.70 (4H, m), 1.70 (9H, s). MS (FAB, m/z): 430 (M⁺ +1), 374, 242, 105, 91.

(1S, 9S) t-Butyl octahydro-10-oxo-9-(3-phenylpropionylamino)-6H-pyridazino -[1,2-a][1,2]diazepine-1-carboxylate (44b), was prepared from (1S, 9S)-t-butyl 9-amino-octahydro-10-oxo-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylate (Attwood et al., J. Chem. Soc. Perkin 1, pp. 1011-19 (1986)) as for 44a, to afford 810 mg (81%) of a colorless oil: [α]_(D) ²³ -33.5° (c 0.545, CH₂ Cl₂); IR (film) 3334, 2935, 1737, 1728, 1659, 1642; ¹ H NMR (CDCl₃) δ 7.24 (5H, m), 6.75 (1H, d, J=6.7), 5.27 (1H, m), 4.92 (1H, m), 3.39 (1H, m), 3.03 (4H, m), 2.55 (3H, m), 2.33 (1H, m), 2.17 (1H, m), 1.80 (5H, m), 1.47 (9H, s), 1.39 (1H, m). MS (FAB, m/z): 416 (M⁺ +1), 360, 211, 143, 97.

(1S, 9S) 6,10-Dioxo-octahydro-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylic acid (45a). To a solution of (1S, 9S) t-butyl 6,10-dioxo-octahydro-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylate (44a) (800 mg; 1.863 mmol) in dry dichloromethane (5 ml) at 0° C. was added trifluoroacetic acid (5 ml). The solution was stirred at room temperature for 3 h then concentrated. Dry ether (10 ml) was added to the residue then removed under vacuum. This process was repeated three times to afford a crystalline solid. The solid was triturated with ether and filtered to afford 590 mg (85%) of a white crystalline solid: mp. 196°-197.5° C.; [α]_(D) ²³ -129.5° (c 0.2, CH₃ OH); IR (KBr) 3237, 1729, 1688, 1660, 1633, 1574, 1432, 1285, 1205; ¹ H NMR (CD₃ OD) δ 8.28 (1H, d, J=7.4), 7.22 (5H, m), 5.32 (1H, dd, J=5.9, 2.9), 4.75 (1H, m), 4.51 (1H, m), 3.50 (1H, m), 3.01 (1H, m), 2.91 (2H, m), 2.55 (2H, m), 2.29 (3H, m), 1.95 (2H, m), 1.71 (2H, m). Anal. Calcd for C₁₉ H₂₃ N₃ O₅ : C, 61.12; H, 6.21; N, 11.25. Found: C, 60.80; H, 6.28; N, 10.97. MS (FAB, m/z) 374 (M⁺ +1), 242, 105, 91.

(1S, 9S) Octahydro-10-oxo-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a]-[1,2]diazepine-1-carboxylic acid (45b), was prepared from (1S, 9S) t-butyl octahydro-10-oxo-9-(3-phenylpropionylamino )-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylate (44b) by the method described for compound 45a to afford 657 mg (96%) of 45b as a crystalline solid: mp. 198°-202° C.; [α]_(D) ²³ -86.2° (c 0.5, CH₃ OH); IR (KBr) 3294, 2939, 1729, 1645, 1620, 1574, 1453, 1214; ¹ H NMR (CD₃ OD) δ 7.92 (1H, d, J=7.9), 7.20 (5H, m), 5.29 (1H, m), 4.90 (1H, m), 3.47 (1H, m), 3.08 (2H, m), 2.90 (2H, m), 2.55 (3H, m), 2.36 (1H, m), 1.81 (5H, m), 1.43 (2H, m). MS (FAB, m/z) 360 (M⁺ +1), 211, 143, 91.

[3S, 2RS, (1S, 9S)] N-(2-Benzyloxy-5-oxotetrahydrofuran-3-yl)-6,10-dioxo-octahydro-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxamide (46a). To a solution of (1S, 9S) 6,10-dioxo-octahydro-9-(3-phenyl-propionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxylic acid (45a) (662 mg; 1.773 mmol) in dry dichloromethane (9 ml) and dry dimethyl formamide (3 ml) at room temperature was added bis(triphenylphosphine)palladium chloride (30 mg) and (3S, 2RS)-3-allyloxycarbonylamino-2-benzyloxy-5-oxotetrahydrofuran (Chapman, Biorg. Med. Chem. Lett., 2, pp. 613-18 (1992)) (568 mg; 1.95 mmol) followed by dropwise addition of tri-n-butyltin hydride (1.19 g; 4.09 mmol). 1-Hydroxy-benzotriazole (479 mg; 3.546 mmol) was added to the mixture and the mixture was cooled to 0° C. before addition of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (408 mg; 2.128 mmol). The mixture was stirred at room temperature for 3.25 h then diluted with ethyl acetate (50 ml), washed twice with dilute hydrochloric acid (20 ml), twice with saturated sodium bicarbonate (20 ml), once with brine then dried (MgSO₄) and concentrated. The resulting oil was purified by flash chromatography (0-100% ethyl acetate/chloroform) to afford 810 mg (81%) of 46a as a mixture of anomers: mp. 92°-94° C.; IR (KBr) 3311, 1791, 1659, 1651, 1536; ¹ H NMR (CDCl₃) δ 7.49, 6.56 (1H, 2d, J=6.7, 7.8), 7.29 (10H, m), 6.37, 6.18 (1H, 2d, J=7.7, 7.6), 5.56, 5.34 (1H, d, s, J=5.2), 5.08-4.47 (6H), 3.18-2.80 (5H), 2.62-2.28 (5H), 2.04-1.53 (5H). MS (FAB, m/z), 563 (M⁺ +1), 328, 149, 91.

[3S, 2RS, (1S, 9S)] N-(2-Benzyloxy-5-oxotetrahydrofuran-3-yl)-octahydro-10-oxo-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxamide (46b), was prepared from 45b by the method described for 46a to yield 790 mg (96%) of a glass: m.p. 58°-60° C.; IR (KBr) 3316, 2940, 1793, 1678, 1641, 1523, 1453, 1120; ¹ H NMR (CDCl₃) δ 7.28 (10H, m), 6.52, 6.42 (1H, 2d, J=7.2, 7.1), 5.53, 5.44 (1H, d, s, J=5.2), 5.35 (1H, m), 4.6-4.9, 4.34 (4H, m), 3.1-2.8 (6H, m), 2.6-2.1 (7H), 1.95-1.05 (5H). MS (FAB, m/z), 549 (M⁺ +1), 400, 310, 279, 91.

[3S, (1S, 9S)] 3-(6,10-Dioxo-octahydro-9-(3-phenylpropionylamino)-6H -pyridazino[1,2-a][1, 2]diazepine-1-carboxamido)-4-oxobutanoic acid (47a). A mixture of [3S, 2RS, (1S, 9S)] N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)-6,10-dioxo-octahydro-9-(3-phenylpropionylamino)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxamide (46a) (205 mg; 0.364 mmol), 10% palladium on carbon (200 mg) and methanol (20 ml) was stirred under hydrogen at atmospheric pressure for 5 h. The mixture was filtered then concentrated to yield 154 mg (90%) of a glass: mp. 116°-118° C.; [α]_(D) ²³ -140° (c 0.1, CH₃ OH); IR (KBr) 3323 (br), 1783, 1731, 1658, 1539, 1455, 1425; ¹ H NMR (CD₃ OD) δ 7.21 (5H, m), 5.17 (1H, m), 4.73 (1H, m), 4.50 (2H, m), 4.23 (1H, m), 3.38 (1H, m), 3.06 (1H, m), 2.91 (2H, m), 2.73-2.18 (6H, m) and 2.01-1.59 (5H, m). Anal. Calcd for C₂₃ H₂₇ N₄ O₇ +H₂ O: C, 56.32; H, 6.16; N, 11.42. Found: C, 56.29; H, 6.11; N, 11.25. MS (FAB, m/z) 473 (M⁺ +1), 176, 149, 105, 91.

[3S, (1S, 9S)] 3-(Octahydro-10-oxo-9-(3-phenylpropionylamino)-6H-pyridazino -[1,2-a][1,2 ]diazepine-1-carboxamido)-4-oxobutanoic acid (47b), was prepared from 46b by the method described for 47a. The residue was purified by flash chromatography (0-10% methanol/chloroform) to afford 65 mg (52%) of a glass; m.p. 87°-90° C.; [α]_(D) ²³ -167.0° (c 0.1, methanol); IR (KBr) 3329, 2936, 1786, 1727, 1637; ¹ H NMR (CD₃ OD) δ 7.23 (5H, m), 5.29 (1H, m), 4.83 (1H, m), 4.59 (1H, d, J=3.6), 4.29 (1H, m), 3.3-3.0 (3H, m), 2.91 (2H, m), 2.70-2.34 (5H, m), 2.19 (2H, m), 1.75 (4H, m), 1.36 (2H, m). Anal. Calcd for C₂₃ H₃₀ N₄ O₆ +0.5H₂ O: C, 59.09; H, 6.68; N, 11.98. Found: C, 58.97; H, 6.68; N, 11.73. MS (FAB, m/z) 459 (M⁺ +1), 310, 149, 105, 91.

    ______________________________________                                          ##STR102##                                                                     ##STR103##                                                                           R.sub.1   R.sub.2     R.sub.3                                           ______________________________________                                         (a)      PhCH.sub.2  H           (S)Me                                         (b)      PhCH.sub.2  CH.sub.2 Ph H                                             (c)      PhCH.sub.2  (CH.sub.2).sub.2 Ph                                                                        H                                             (d)      PhCH.sub.2  nBu         H                                             (e)      PhCH.sub.2  Me          H                                             (f)      PhCH.sub.2  Ph          H                                             (g)      PhCH.sub.2  H           H                                             (h)      PhCH.sub.2  CH.sub.2 Ph (S)Me                                         (i)      Ph(CH.sub.2).sub.2                                                                         CH.sub.2 Ph H                                             ______________________________________                                    

Pyridones 48 were prepared by the method described by Damewood et al., J. Med. Chem., 37, pp. 3303-12 (1994)). Compound 48d is new.

3-Benzyloxycarbonylamino-6-butyl-pyrid-2-one (48d), was isolated as a cream solid: mp. 158°-160° C.; IR (KBr) 3382, 2953, 2930, 2866, 1729, 1643, 1524, 1468, 1202, 1044; ¹ H NMR (d₆ -DMSO) δ 8.26 (1H, s), 7.72 (1H, d), 7.39 (5H, m), 6.00 (1H, d), 5.14 (2H, s), 2.41 (2H, t), 1.52 (2H, m), 1.24 (2H, m), 0.87 (3H, t). Anal. Calcd for C₁₇ H₂₀ N₂ O₃ : C, 67.98; H, 6.71; N, 9.33. Found: C, 67.69; H, 6.68; N, 9.20. MS CI M⁺ =300 (m)) 28%.

(2S) Methyl 2-[3-benzyoxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl]propionate (49a). Sodium hydride (80% oil dispersion) (0.359, 11.64 mmole) was added to a stirred mixture of 3-(benzyloxycarbonylamino)pyrid-2-one (48a) (2.58 g, 10.58 mmol) and tetrahydrofuran (100 ml) at room temperature. The mixture was stirred for 10 mins. The resulting solution was added to a solution of 2(R) methyl-2((trifluoromethane) sulphonyloxy)propionate (2.5 g, 10.58 mmole; Feenstra et al., Tetrahedron Lett., 28, pp. 1215-18 (1987)) in tetrahydrofuran (5 ml) at room temperature during 10 mins. The mixture was stirred at room temperature for 80 mins then poured into ethyl acetate. The mixture was washed twice with 1M HCl, twice with aqueous sodium bicarbonate then brine. It was dried (MgSO₄) and concentrated. The residue was purified by flash chromatography (30% ethyl acetate/hexane) to afford 2.945 g (84%) of a colorless solid: mp. 96°-7°; [α]_(D) ²⁰ -71.36 (c 2.5, CHCl₂); IR (KBr) 3370, 1764, 1729, 1648, 1602, 1564, 1523, 1515, 1503, 1449, 1359, 1203, 1064; ¹ H NMR (CDCl₃) δ 8.04 (1H, d, J=7.2), 7.86 (1H, s), 7.36 (5H, m), 6.98 (1H, dd, J=7.1, J=1.7), 6.30 (1H, t, J=7.2), 5.46 (1H, q, J=7.4), 5.20 (2H, s), 3.74 (3H, s), 1.66 (3H, d, J=7.4). Anal. Calcd for C₁₇ H₁₈ N₂ O₅ : C, 61.81; H, 5.49; N, 8.48. Found: C, 61.49; H, 5.51; N, 8.41. MS (FAB, m/z) 331 (M⁺ +1), 299, 223, 196, 163, 91.

Methyl [6-benzyl-3-benzyloxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl]-acetate (49b). Sodium hydride (80% oil dispersion) (0.65 g, 26.2 mmole) was added to a stirred mixture of 6-benzyl-3(benzyloxycarbonylamino) pyrid-2-one (48b) (7.3 g, 2.18 mmol) and tetrahydrofuran (150 ml) at room temperature. The mixture was stirred for 10 mins, treated with methyl bromoacetate (2.5 ml, 26.2 mmol) and kept for 3 h. The resulting mixture was poured onto a mixture of ice and 1M HCl. The resulting solid was filtered off then dissolved in dichloromethane. The resulting solution was dried (MgSO₄), decolourised with charcoal and concentrated. The residue was purified by chromatography (2-5% ethyl acetate/dichloromethane) to afford 7.2 g (81%) of colorless crystals: mp. 117°-9°; IR (KBr) 3375, 1753, 1730, 1651, 1605, 1513, 1384, 1223, 1185, 1071; ¹ H NMR δ 8.02 (1H, d, J=7.5), 7.78 (1H, s), 7.31 (8H, m), 7.10 (2H, m), 7.15 (1H, d, J=7.5), 5.20 (2H, s), 4.70 (2H, s), 3.88 (2H, s), 3.66 (3H, s).

The following compounds were prepared in a similar manner:

Methyl [3-benzyloxycarbonylamino-1,2-dihydro-2-oxo-6-phenethyl-1-pyridyl]-acetate (49c). 97% yield: m.p. 102°-4° C. IR (KBr) 3245, 3232, 1741, 1725, 1648, 1600, 1526, 1216; ¹ H NMR (d₆ -DMSO) δ 8.45 (1H, s), 7.76 (1H, d, J=7.6), 7.35 (10H, m), 6.15 (1H, d, J=7.6), 5.15 (2H, s), 4.85 (2H, s), 3.68 (3H, s), 2.86 (4H, s).

Methyl [3-benzyloxycarbonylamino-6-butyl-1,2-dihydro-2-oxo-1-pyridyl]-acetate (49d). 90% yield: mp. 111°-112° C.; IR (KBr) 3393, 1738, 1731, 1645, 1598, 1517, 1225, 1208; ¹ H NMR (d₆ -DMSO) δ 8.39 (1H, s), 7.78 (1H, d, J=7.7), 7.35 (5H, m), 6.17 (1H, d, J=7.7), 5.15 (2H, s), 4.80 (2H, s), 3.67 (3H, s), 1.38 (6H, m), 0.89 (3H, t).

Methyl [3-benzyloxycarbonylamino-1,2-dihydro-6-methyl -2-oxo-1-pyridyl]-acetate (49e). 84% yield as a colorless solid: mp. 115°-6° C.; IR (KBr) 3246, 1740, 1725, 1649, 1598, 1573, 1535, 1417, 1365, 1259, 1219, 1193, 1090, 1068, 1006; ¹ H NMR (d₆ -DMSO) δ 8.40 (1H, s), 7.75 (1H, d, J=7.6), 7.38 (5H, m), 6.20 (1H, d, J=7.6), 5.15 (2H, s), 4.85 (2H, s), 3.68 (3H, s), 2.26 (3H, s).

Methyl [3-benzyloxycarbonylamino-1,2-dihydro-6-phenyl-1-pyridyl]-acetate (49f). 67% yield as a colorless oil: IR (KBr) 3266, 1739, 1727, 1646, 1606, 1566, 1517, 1490, 1365, 1213, 1163, 1075; ¹ H NMR (CDCl₃) δ 8.15 (1H, d), 7.85 (1H, s), 7.39 (10H, m), 6.22 (1H, d), 5.22 (2H, s), 4.57 (2H, s), 3.74 (3H, s).

Methyl [3-benzyloxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl]-acetate (49 g). 80% yield as a colorless crystalline solid: m.p. 110°-111° C. IR (KBr) 3385, 1745, 1726, 1650, 1601, 1512, 1502, 1378, 1369, 1358, 1215, 1195, 1162, 1067; ¹ H NMR (CDCl₃) δ 8.06 (1H, d), 7.84 (1H, s), 7.36 (5H, m), 6.88 (1H, dd), 6.27 (1H, t), 5.20 (2H, s), 4.68 (2H, s), 3.78 (3H, s). Anal. Calcd for C₁₆ H₁₆ N₂ O₅ : C, 60.75; H, 5.10; N, 8.85. Found: C, 60.65; H, 5.15; N, 8.85. MS FAB (+) M+=317 (M+1).

2(S) Methyl 2-methyl-[6-benzyl-(3-benzyloxycarbonylamino)-1,2-dihydro-2-oxo-1-pyridyl]-acetate (49h), was prepared by the method used in the preparation of compound 49a to afford (58%) an oil; [α]_(D) ²⁵ -25.0° (c 1, CH₂ Cl₂); IR (KBr) 3381, 1736, 1650, 1604, 1513, 1218, 1190, 1068; ¹ H NMR (CDCl₃) δ 7.97 (1H, d), 7.78 (1H, s), 7.4-7.14 (10H, m), 6.17 (1H, d), 5.19 (2H, s), 4.64 (1H, q), 3.98 (2H, s), 3.62 (3H, s), 1.31 (3H, d).

Methyl [6-benzyl-1,2-dihydro-2-oxo-3-(2-phenylethoxy)-carbonylamino-1-pyridyl]acetate (49i), was isolated (88%) as a colorless solid: mp. 130°-133° C.; IR (KBr) 3363, 1746, 1732, 1651, 1604, 1515, 1368, 1231, 1212, 1185; ¹ H NMR (CDCl₃) δ 8.00 (1H, d, J=7.0), 7.68 (1H, s), 7.36-7.10 (10H, m), 6.15 (1H, d, J=7.6), 4.7 (2H, s), 4.38 (2H, t, J=7.0), 3.88 (2H, s), 3.67 (3H, s), 2.98 (2H, t, J=7). ##STR104##

2(S) Methyl 2[3-amino-1,2-dihydro-2-oxo-1-pyridyl]propionate (50a). A mixture of 2(S) methyl-2[3-benzyloxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl)propionate (49a) (2.75 g, 8.33 mmol), methanol (100 ml), and 10% palladium on carbon (300 mg) was stirred under an atmosphere of hydrogen for 30 min. The mixture was filtered and concentrated to afford 1.63 g (100%) of a colorless solid: ¹ H NMR (d₆ -DMSO) δ 8.35 (1H, brs), 7.46 (1H, d), 7.22 (1H, d), 6.29 (1H, t), 5.22 (1H, q), 3.63 (3H, s), 1.55 (3H, d).

The following compounds were prepared in a similar manner:

Methyl [3-amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl]acetate (50b). 100% yield as a grey solid: mp. 134°-6° C.; IR (KBr) 3418, 3312, 1723, 1658, 1596, 1548, 1435, 1290, 1245, 1011; ¹ H NMR (d₆ -DMSO) δ 7.25 (5H, m), 6.45 (1H, d, J=7.4), 5.92 (1H, d, J=7.4), 5.00 (2H, s), 4.63 (2H, s), 3.88 (2H, s), 3.51 (3H, s).

Methyl [3-amino-1,2-dihydro-2-oxo-6-phenethyl-1-pyridyl]acetate (50c). 99% yield as a viscous oil: IR (KBr) 3456, 341, 2953, 1745, 1649, 1600, 1548, 1219; ¹ H NMR (CDCl₃) δ 7.25 (5H, m), 6.51 (1H, d, J=7.4), 5.92 (1H, d, J=7.4), 4.79 (2H, s), 3.77 (3H, s), 2.80 (4H, m).

Methyl [3-amino-6-butyl-1,2-dihydro-2-oxo-1-pyridyl]acetate (50d). 97% as a brown solid: mp. 75°-7° C.; IR (KBr) 3437, 3342, 2955, 1745, 1655, 1609, 1550, 1432, 1301, 1222, 1200; ¹ H NMR (CDCl₃) δ 6.53 (1H, d, J=6.8), 5.93 (1H, d, J=6.8), 4.81 (2H, s), 3.77 (3H, s), 2.44 (2H, t), 1.45 (4H, m), 0.93 (3H, t).

Methyl [3-amino-1,2-dihydro-6-methyl-2-oxo-1-pyridyl]acetate (50e), was isolated (100%) as a colorless crystalline solid: mp. 87°-9° C.; IR (KBr) 3442, 3326, 1735, 1647, 1600, 1549, 1434, 1407, 1383, 1366, 1225, 1209; ¹ H NMR (d₆ -DMSO) δ 6.40 (1H, d, J=7.3), 5.93 (1H, d, J=7.3), 4.86 (2H, s), 4.79 (2H, s), 3.67 (3H, s), 2.15 (3H, s).

Methyl [3-amino-1,2-dihydro-2-oxo-6-phenyl-1-pyridyl]acetate (50f), was isolated (86%) as a grey solid: mp.207°-9° C.; IR (KBr) 3473, 3345, 1750, 1644, 1600, 1536, 1443, 1366, 1309, 1212, 1184, 1156; ¹ H NMR (d₆ -DMSO) δ 7.30 (5H, m), 6.54 (1H, d), 6.03 (1H, d), 5.25 (2H, s), 4.49 (2H, s), 3.61 (3H, s).

Methyl [3-amino-1,2-dihydro-2-oxo-1-pyridyl]acetate (50g), was obtained as a colorless oil and used immediately in the next step.

2(S) Methyl 2-methyl-[3-amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl]acetate (50h), was isolated (69%) as a colorless oil: IR (film) 3354, 1743, 1646, 1600, 1548, 1494, 1455, 1309, 1268, 1227, 113; ¹ H NMR (C₆ D₆) δ 7.29-6.76 (5H, m), 5.86 (1H, d, J=7.2), 5.51 (1H, d, J=7.2), 4.43 (1H, q, J=6.7), 3.69 (2H, s), 3.41 (2H, s), 3.36 (3H, s), 1.43 (3H, d, J=6.7).

    ______________________________________                                          ##STR105##                                                                     ##STR106##                                                                    R.sub.1          R.sub.2     R.sub.3                                           ______________________________________                                         (a)     Ph(CH.sub.2).sub.2 CO                                                                       H           (S)Me                                         (b)     Ph(CH.sub.2).sub.2 CO                                                                       CH.sub.2 Ph H                                             (c)     Ph(CH.sub.2).sub.2 CO                                                                       (CH.sub.2).sub.2 Ph                                                                        H                                             (d)     Ph(CH.sub.2).sub.2 CO                                                                       nBu         H                                             (e)     Ph(CH.sub.2).sub.2 CO                                                                       Me          H                                             (f)     Ph(CH.sub.2).sub.2 CO                                                                       Ph          H                                             (g)     Ph(CH.sub.2).sub.2 CO                                                                       H           H                                             (h)     Ph(CH.sub.2).sub.2 CO                                                                       CH.sub.2 Ph (S)Me or                                                                       (R,S)Me                                       (i)     AcTyr        CH.sub.2 Ph H                                             (j)     Ph(CH.sub.2).sub.2 SO.sub.2                                                                 CH.sub.2 Ph H                                             (k)     Ph(CH.sub.2).sub.2 OCO                                                                      CH.sub.2 Ph H                                             (l)     Ph(CH.sub.2).sub.3 CO                                                                       CH.sub.2 Ph H                                             ______________________________________                                    

2(S) Methyl 2-[1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-propionate (51a). 3-Phenylpropionyl chloride (1.5 g, 9 mmol) was added dropwise to a stirred mixture of 2S methyl-2-[3-amino-1,2-dihydro-2-oxo-1-pyridyl]propionate (50a) (1.63 g, 8.33 mmol), dioxane (60 ml), water (15 ml) and sodium bicarbonate (1.54 g, 16.7 mmol). The mixture was kept for 1 h then extracted with ethyl acetate. The extracts were washed with aqueous sodium bicarbonate, dried (MgSO₄) and concentrated. The resulting red oil was purified by flash chromatography to afford 2.54 g (93%) of an oil: [α]_(D) ²⁰ -68° C. (1, CH₂ Cl₂); IR (CH₂ Cl₂) 3369, 1747, 1690, 1650, 1602, 1512, 1267, 1260, 1217; ¹ H NMR (CDCl₃) δ 8.41 (1H, dd), 8.36 (1H, s), 7.24 (5H, m), 7.02 (1H, dd), 6.32 (1H, t), 5.44 (1H, q), 3.75 (3H, s), 3.03 (2H, t), 2.70 (2H, t), 1.66 (3H, d). FAB M+=329 (M+1), 197, 165, 131, 110, 91.

The following compounds were prepared in a similar manner:

Methyl [6-benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51b), was isolated (93%) as crystals: mp. 95°-7° C.; IR (KBr) 3265, 1747, 1686, 1642, 1590, 1563, 1511, 1454, 1401, 1220, 1183, 1133; ¹ H NMR (CDCl₃) δ 8.39 (1H, d, J=7.7), 8.27 (1H, s), 7.21 (10H, m), 6.17 (1H, d, J=7.7), 4.70 (2H, s), 3.89 (2H, s), 3.67 (3H, s), 3.02 (2H, m), 2.70 (2H, m).

Methyl [1,2-dihydro-2-oxo-6-phenethyl-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51c), was isolated (81%) as colorless crystals: mp. 105°-8° C.; IR (KBr) 3378, 1746, 1680, 1646, 1597, 1517, 1221; ¹ H NMR (CDCl₃) δ 8.34 (1H, d, J=7.7), 8.25 (1H, s), 7.23 (10H, m), 6.11 (1H, d, J=7.7), 4.77 (2H, s), 3.78 (3H, s), 2.88 (8H, m).

Methyl [6-butyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51d), was isolated (88%) as colorless crystals: mp. 84°-5° C.; IR (KBr) 3345, 2958, 2930, 1756, 1693, 1650, 1602, 1510, 1227, 1180, 1137; ¹ H NMR (CDCl₃) δ 8.34 (1H, d, J=7.7), 8.22 (1H, s), 7.26 (5H, m), 6.12 (1H, d, J=7.7), 4.80 (2H, s), 3.79 (3H, s), 3.03 (2H, t), 2.68 (2H, t), 2.50 (2H, t), 1.46 (4H, m), 0.95 (3H, t).

Methyl [1,2-dihydro-6-methyl-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51e), was isolated (100%) as a pale yellow oil: IR (film) 3264, 1745, 1691, 1644, 1587, 1566, 1518, 1495, 1400, 1215, 1183, 1136; ¹ H NMR (CDCl₃) δ 8.33 (1H, d, J=7.6), 7.26 (5H, m), 6.13 (1H, d, J=7.6), 4.83 (2H, s), 3.79 (3H, s), 3.03 (2H, m), 2.69 (2H, m), 2.28 (3H, s).

Methyl [1,2-dihydro-2-oxo-6-phenyl-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51f), was isolated (99%) as a pale yellow oil: IR (film) 3365, 3299, 1751, 1689, 1643, 1600, 1563, 1519, 1493, 1419, 1370, 1224; ¹ H NMR (CDCl₃) δ 8.46 (1H, d, J=7.7), 8.32 (1H, s), 7.32 (10H, m), 6.24 (2H, d, J=7.7), 4.57 (2H, s), 3.73 (3H, s), 3.06 (2H, m), 2.72 (2H, m).

Methyl [1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51g), was isolated (81%) as an oil: IR (film) 3330, 1753, 1689, 1650, 1600, 1560, 1517, 1374, 1225, 1208; ¹ H NMR (CDCl₃) δ 8.43 (1H, dd, J=7.4, 1.7), 8.33 (1H, s), 7.28 (5H, m), 6.92 (1H, dd, J=6.9, 1.7), 6.29 (1H, t), 4.67 (2H, s), 3.79 (3H, s), 3.04 (2H, m), 2.70 (2H, m). MS FAB (+) M+=315 (M+1).

2(S) Methyl 2-methyl-[6-benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-acetate (51h), was isolated (93%) as a colorless oil; [α]_(D) ³⁰ -19° (c 1, CH₂ Cl₂); IR (film) 3354, 3313, 3028, 2950, 1745, 1687, 1645, 1600, 1567, 1514, 1454, 1225; ¹ H NMR (CDCl₃) δ 8.35 (1H, d, J=7.5), 8.26 (1H, s), 7.27 (10H, m), 6.20 (1H, d, J=7.5), 4.65 (1H, q, J=6.8), 3.99 (2H, s), 3.71 (3H, s), 3.03 (2H, m), 2.68 (2H, m), 1.31 (3H, d, J=6.8).

Methyl [3-(N-acetyl-O-benzyl-L-tyrosine)amino-6-benzyl-1,2-dihydro-2-oxo-pyridyl]acetate (51i). A stirred mixture of methyl [3-amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl]acetate (100 mg, 0.367 mmol), Boc-Tyr(Bn)-OH (136 mg, 0.367 mmol), dimethylformamide (1 ml), diisopropylethylamine (0.25 ml, 1.468 mmol) and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (118 mg, 0.367 mmol) was kept overnight at room temperature. The mixture was diluted with ethyl acetate, washed twice with 1M hydrochloric acid, twice with aqueous sodium bicarbonate, once with brine, then dried (MgSO₄) and concentrated. The residue was purified by flash chromatography (10% ethylacetate/dichloromethane) to afford a 162 mg (70%) of a colorless oil. The oil (160 mg, 0.255 mmol) was dissolved in dichloromethane (1 ml) and treated with trifluoroacetic acid (1 ml) at 0° C. The resulting solution was allowed to reach room temperature during 40 min then evaporated to dryness at 30° C. The residue was dissolved in dichloromethane then evaporated to dryness again. This procedure was repeated three times. The residue was dissolved in pyridine (0.5 ml) and treated with acetic anhydride (0.03 ml, 0.3 mmol) at 0° C. The resulting mixture was allowed to reach room temperature and kept for 3.5 h. It was diluted with ethyl acetate, washed twice with 1M hydrochloric acid, twice with aqueous sodium bicarbonate, dried (MgSO₄) and concentrated to afford 128 mg (86%) of a colorless oil: IR (film) 3290, 1751, 1649, 1602, 1568, 1513, 1455, 1438, 1375, 1224, 1179; ¹ H NMR (CDCl₃) δ 8.78 (1H, s), 8.33 (1H, d, J=7.6), 7.33 (8H, m), 7.11 (4H, m), 6.86 (2H, d, J=8.5), 6.47 (1H, d, J=7.6), 6.12 (1H, d, J=7.6), 4.99 (2H, s), 4.85 (1H, m), 4.69 (2H, s), 3.87 (2H, s), 3.62 (3H, s), 3.08 (2H, m), 1.96 (3H, s).

Methyl [6-benzyl-1,2-dihydro-2-oxo-3-(2-phenylethanesulphonyl)amino-1-pyridyl]-acetate (51j). 2-Phenylethanesulphonyl chloride (Zhong et al., J. Am. Chem. Soc., 113, pp. 2259-63 (1991)) was added to a stirred mixture of methyl [3-amino-6-benzyl-2-oxo-1,2-dihydro-1-pyridyl]-acetate (49b) (1.0 g, 3.67 mmol), dichloromethane (15 ml) and triethylamine (1.0 ml, 7.34 mmol). The mixture was kept overnight then poured into ethyl acetate. The resulting mixture was washed twice with aqueous sodium bicarbonate, three times with 1M hydrochloric acid, then brine. It was dried (MgSO₄) and concentrated. The resulting pale brown solid was purified by flash chromatography (10% ethylacetate/dichloromethane) to afford 1.25 g (77%) of a pale yellow solid: m.p. 92°-4° C.; IR (KBr) 3181, 1737, 1646, 1595, 1565, 1454, 1241, 1220, 1150; ¹ H NMR (CDCl₃) δ 7.53 (1H, d, J=7.5), 7.29 (10H, m), 6.10 (1H, d, J=7.5), 4.75 (2H, s), 3.89 (2H, s), 3.67 (3H, s), 3.34 (2H, m), 3.14 (2H, m).

Methyl [6-benzyl-1,2-dihydro-2-oxo-3-(4-phenylbutyryl)amino-1-pyridyl]-acetate (51l), was isolated (74%) as colorless crystals: mp. 93°-95° C.; IR (KBr) 3285, 1747, 1683, 1642, 1591, 1563, 1512, 1455, 1220, 1181; ¹ H NMR (CDCl₃) δ 8.39 (1H, d, J=7.6), 8.24 (1H, s), 7.2 (10H, m), 6.18 (1H, d, J=7.6), 4.7 (2H, s), 3.90 (2H, s), 3.67 (3H, s), 2.69 (2H, t), 2.40 (2H, t), 2.04 (2H, m). ##STR107##

2(S) 2-[1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino)-1-pyridyl]propionic acid (52a). 1M Sodium hydroxide (15 ml, 15 mmol) was added to a stirred solution of 2(S) methyl 2-[1,2-dihydro-2-oxo-3(3-phenylpropionyl)amino-1-pyridyl]propionate (51a) (2.39 g, 7.3 mmol) in methanol (30 ml) at 0° C. The mixture was kept at this temperature for 2 h, acidified with 1M hydrochloric acid (15.1 ml) and extracted with ethyl acetate. The extracts were washed with brine, dried (MgSO₄) and concentrated to afford 1.98 g (87%) of a colorless solid: [α]_(D) ²⁰ -75° (1, CH₂ Cl₂); IR (KBr) 3301, 1724, 1693, 1637, 1563, 1523, 1453, 1233, 1216, 765; ¹ H NMR (CDCl₃) δ 8.47 (2H, m), 7.20 (5H, m), 7.03 (1H, d), 6.36 (1H, t), 5.35 (1H, q), 3.01 (2H, m), 2.70 (2H, m), 1.69 (3H, m).

The following compounds were prepared in a similar manner:

[6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]acetic acid (52b), was isolated (100%) as a pale amber oil: IR (film) 3291, 1738, 1686, 1644, 1591, 1554, 1519, 1496, 1454, 1403, 1215, 1182; ¹ H NMR (CDCl₃) δ 8.44 (1H, d, J=7.8), 8.4 (1H, s), 7.21 (10H, m), 6.19 (1H, d, J=7.8), 4.71 (2H, s), 3.90 (2H, s), 2.99 (2H, m), 2.71 (2H, m).

[1,2-Dihydro-2-oxo-6-phenethyl-3-(3-phenylpropionyl)amino-1-pyridyl]acetic acid (52c), was isolated (94%) as a beige solid: mp. 214°-6° C.; IR (KBr) 3289, 1740, 1680, 1640; ¹ H NMR (d₆ -DMSO) δ 9.24 (1H, s), 8.14 (1H, d, J=7.7), 7.22 (10H, m), 6.11 (1H, d, J=7.8), 4.78 (2H, s), 2.81 (8H, m).

[6-Butyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]acetic acid (52d), was isolated (99%) as a pale brown solid: mp. 132°-4° C.; IR (KBr) 3286, 1739, 1676, 1641, 1554, 1555, 1535, 1455, 1414, 1249, 1227, 1204; ¹ H NMR (CDCl₃) δ 8.42 (1H, d, J=7.8), 8.37 (1H, s), 7.24 (5H, m), 6.19 (1H, d, J=7.8), 4.82 (2H, s), 3.55 (1H, s), 3.00 (2H, t), 2.67 (2H, t), 2.53 (2H, t), 1.41 (4H, m), 0.94 (3H, t).

[1,2-Dihydro-6-methyl-2-oxo-3-(3-phenylpropionyl)amino-10 1-pyridyl]acetic acid (52e), was isolated as a solid (100%): mp. 159°-61° C.; IR (KBr) 3335, 1731, 1686, 1642, 1536, 1516, 1430, 1420, 1401, 1222, 1195; ¹ H NMR (d₆ -DMSO) δ 9.21 (1H, s), 8.13 (1H, d, J=7.6), 7.20 (5H, m), 6.15 (1H, d, J=7.6), 4.77 (2H, s), 2.87 (2H, m), 2.70 (2H, m), 2.25 (3H, s).

[1,2-Dihydro-2-oxo-6-phenyl-3-(3-phenylpropionyl)amino-1-pyridyl]acetic acid (52f), was isolated (100%) as a pale yellow foam: IR (KBr) 3271, 1747, 1683, 1634, 1580, 1536, 1490, 1406, 1392, 1365, 1235, 1219; ¹ H NMR (CDCl₃) δ 8.52 (1H, d, J=7.7), 7.31 (10H, m), 6.48 (2H, s), 6.30 (1H, d, J 7.7), 4.60 (2H, s), 3.03 (2H, m), 2.71 (2H, m).

[1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]acetic acid (52g), was isolated (94%) as a colorless solid: mp. 195°-7° C.; IR (KBr) 3324, 1724, 1693, 1644, 1569, 1555, 1512, 1427, 1370, 1240; ¹ H NMR (d₆ -DMSO) δ 9.31 (1H, s), 8.23 (1H, d, J=6.8), 7.36 (1H, dd, J=6.8, 1.71), 7.25 (5H, m), 6.25 (1H, t), 4.66 (2H, s), 2.84 (4H, m).

2(R,S) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-propionic acid (52h), was prepared by hydrolysis of compound 51 h in aqueous tetrahydrofuran during 5 h at 40° C. to afford (95%) as a yellow oil: IR (film) 3330, 1734, 1686, 1643, 1600, 1587, 1553, 1524, 1498, 1208; ¹ H NMR (d₆ -DMSO) δ 9.29 (1H, s), 8.18 (1H, d, J=7.6), 7.21 (10H, m), 6.22 (1H, d, J=7.6), 4.82 (1H, q, J=6.6), 4.08 (2H, m), 2.76 (4H, m), 1.05 (3H, d, J=6.6).

[3-(Acetyl-Tyr(Bn))amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl]acetic acid (52i), was isolated (93%) as a foam: IR (KBr) 3302, 1731, 1646, 1603, 1562, 1512, 1454, 1428, 1379, 1231, 1178; ¹ H NMR (CDCl₃) δ 9.48 (1H, s), 8.36 (1H, d, J=7.6), 7.30 (8H, m), 7.10 (2H, m), 6.85 (2H, d, J=8.3), 6.91 (2H, d, J=8.3), 6.71 (1H, d, J 7.6), 4.95 (1H, m), 4.90 (2H, s), 4.68 (2H, s), 3.92 (2H, s), 3.17-2.83 (2H, m), 1.92 (3H, s).

[6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethanesulphonyl)amino-1-pyridyl]acetic acid (52j), was isolated (100%) as a colorless solid: mp. 165°-7° C.; IR (KBr) 3174, 1760, 1646, 1593, 1567, 1497, 1453, 1424, 1326, 1225, 1140, 1127; ¹ H NMR (d₆ -DMSO) δ 13.09 (1H, s), 9.08 (1H, s), 7.30 (11H, m), 6.02 (1H, d), 4.68 (2H, s), 4.99 (2H, s), 3.29 (2H, m), 3.03 (2H, m).

[6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethoxy)carbonylamino-1-pyridyl]acetic acid (52k), was prepared (70%) by hydrolysis of compound 49i during 1 h at 60° C.: IR (CH₂ Cl₂) 1797, 1689, 1649, 1601, 1512, 734; ¹ H NMR (CDCl₃) δ 8.39 (1H, s), 8.03 (1H, d), 7.81 (1H, s), 7.33-7.07 (10H, m), 6.13 (1H, d, J=7.8), 4.72 (2H, s), 4.33 (2H, t, J=7.0), 3.86 (2H, s), 2.93 (2H, t, J=7.0).

[6-Benzyl-1,2-dihydro-2-oxo-3-(4-phenylbutyryl)amino-1-pyridyl]acetic acid (52l), was isolated (100%) as a white foam: m.p. 159°-161° C.; IR (KBr) 3373-3310, 1787, 1726, 1691, 1649, 1599, 1567, 1517, 1367, 1215; ¹ H NMR (CDCl₃) δ 8.43 (1H, d, J=7.7), 8.25 (1H, s), 7.37-7.09 (10H, m), 6.21 (1H, d, J=7.7), 4.73 (2H, s), 4.15 (3H, s), 3.91 (2H, s), 2.67 (2H, t), 2.39 (2H, t), 2.02 (2H, m). ##STR108##

2(S), N-3(S) 2-[1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)propionamide (53a). Tri-n-butyltin hydride (1.7 ml, 6.3 mmol) was added dropwise to a stirred mixture of 2(S)-2-[1,2-dihydro-2-oxo-3(3-phenylpropionyl)amino-1-pyridyl]propionic acid (52a) (1.1 g, 3.49 mmol), 3(S), 2(R,S) 3-allyloxycarbonylamino-2-benzyloxy-5-oxotetrahydrofuran (1.02 g, 3.49 mmol; Chapman, Biorg. Med. Chem. Lett., 2, pp. 613-18 (1992)), bis(triphenylphosphine)palladium (II) chloride (55 mg), dichloromethane (35 ml) and dimethylformamide (1 ml). The resulting mixture was stirred for 5 min. then 1-hydroxybenzotriazole (946 mg, 7 mmol) was added. The mixture was cooled to 0° C. before the addition of 1-(3-dimethylaminopropyl)-2-ethylcarbodiimide hydrochloride (740 mg, 3.84 mmol). The mixture was kept overnight at room temperature then poured into ethyl acetate. The mixture was washed twice with 1M hydrochloric acid, twice with aqueous sodium bicarbonate, then brine. The mixture was dried (MgSO₄) and concentrated. The residue was triturated with pentane. The remaining solid was purified by flash chromatography (40-60% ethyl acetate/hexane) to afford 1.28 g (73%) of colorless solid: IR (KBr) 1796, 1692, 1647, 1595, 1557, 1512, 1119; ¹ H NMR (d₆ -DMSO) δ 9.28, 9.26 (1H, 2×s), 8.77, 8.69 (1H, 2×d), 8.24, 8.20 (1H, 2×dd), 7.20 (11H, m), 6.31, 6.26 (1H, 2×t), 5.65 (0.5H, d), 5.46 (0.5H, d), 5.41, 5.28 (1H, 2×q), 4.7 (2.5H, m), 4.24 (0.5H, t), 3.24 (2H, m), 2.80 (4H, m), 1.51, 1.46 (3H, 2×d).

The following compounds were prepared in a similar manner:

N(3(S)) 2[6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53b), was obtained (86%) as a foam: IR (KBr) 3345, 3297, 1807, 1791, 1688, 1679, 1650, 1602, 1554, 1525, 1497, 1453, 1372, 1257, 1119; ¹ H NMR (d₆ -DMSO) δ 9.25 (0.5H, s), 9.23 (0.5H, s), 8.75 (0.5H, d, J=6.5), 8.67 (0.5H, d, J=7.4), 8.18 (1H, 2d), 7.21 (15H, m), 6.07 (1H, 2d), 5.65 (0.5H, d, J=5.0), 5.38 (0.5H, s), 4.83-4.45 (4.5H, m), 4.19 (0.5H, m), 3.94, 3.83 (2H, m), 3.10-2.31 (6H, m).

N(3(S)) 2[1,2-Dihydro-2-oxo-6-phenethyl-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-4-yl)acetamide (53c), was obtained (74%) as a mixture of anomers: ¹ H NMR (d₆ -DMSO) δ 9.71 (1H, d), 9.41 (0.5H, d), 9.25 (0.5H, d), 8.64 (1H, d, J=7.7), 7.75 (15H, m), 6.61 (1H, 2d), 6.11 (0.5H, d), 5.93 (0.5H, s), 5.17 (5H, m), 4.77 (0.5H, m), 3.68-2.94 (2H, m), 3.32 (8H, m).

N(3(S)) 2[6-Butyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl) acetamide (53d), was obtained (74%) as a mixture of anomers: IR (KBr) 3300, 1791, 1689, 1645, 1597, 1566, 1546, 1514, 1454, 1417, 1378; ¹ H NMR (CDCl₃) δ 8.38 (1H, d, J=7.7), 8.13 (1H, s), 7.30 (10H, m), 6.18 (1H, t), 5.47 (0.5H, d, J=5.2), 5.43 (0.5H, s), 4.75 (4.5H, m), 4.38 (0.5H, m), 3.08-2.35 (8H, m), 1.43 (4H, m), 0.95 (3H, t).

N(3(S)) 2[1,2-Dihydro-6-methyl-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53e), was obtained (67%) as a mixture of anomers: IR (KBr) 3282, 1774, 1667, 1651, 1596, 1561, 1556, 1498, 1265, 1254, 1236, 1199, 1143; ¹ H NMR (d₆ -DMSO) δ 9.17 and 9.15 (1H, 2×s), 8.89 (0.5H, d, J=6.5), 8.73 (0.5H, d, J=7.4), 7.25 (10H, m), 6.13 (1H, t), 5.64 (0.5H, d, J=5.0), 5.45 (0.5H, s), 4.89-4.61 (4.5H, m), 4.26 (0.5H, m), 3.17-2.36 (6H, m), 2.23 and 2.15 (3H, 2s).

N(3(S)) 2-[1,2-Dihydro-2-oxo-6-phenyl-3(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53f), was obtained (73%) as a mixture of anomers: IR (KBr) 3296, 1792, 1691, 1643, 1595, 1561, 1514, 1489, 1453, 1420, 1373, 1230, 1118; ¹ H NMR (d₆ -DMSO) δ 9.40, 9.36 (1H, 2s), 8.70 (0.5H, d, J=7.6), 8.52 (0.5H, d, J=7.5), 8.29 (1H, dd), 7.25 (15H, m), 6.20 (1H, d, J=7.6), 5.61 (0.5H, d, J=5.0), 5.28 (0.5H, s), 4.78-4.20 (5H, m), 3.12-2.24 (6H, m).

N(3(S)) 2-[1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53g), was obtained (70%) as a mixture of anomers: IR (KBr) 3336, 3290, 1791, 1691, 1646, 1595, 1582, 1556, 1518, 1454, 1376, 1351, 1150, 1122; ¹ H NMR (d₆ -DMSO) δ 9.26 (1H, 2s), 8.86 (0.5H, d, J=6.4), 8.67 (0.5H, d, J=7.5), 8.23 (1H, m), 7.40-7.13 (11H, m), 6.24 (1H, 2t, J=7.2), 5.61 (0.5H, d, J=5.0), 5.44 (0.5H, s), 4.83-4.59 (2.5H, m), 4.25 (0.5H, m), 3.15-2.34 (2H, m), 2.91-2.70 (4H, m). Anal. Calc. for C₂₇ H₂₇ N₃ O₆ H₂ O: C, 63.90; H, 5.76; N, 8.28. Found: C 63.70; H, 5.68; N, 8.22. MS FAB M+=490 (M+1).

2(R, S), N(3(S)) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N(2-benzyloxy-5-oxotetrahydrofuran-3-yl)propionamide (53h), was obtained (89%) as a mixture of diastereomers. Data is given for a single diastereomer: IR (film) 3356, 1788, 1677, 1645, 1602, 1517, 1455, 1377, 1203, 1167, 1120; ¹ H NMR (CDCl₃) δ 8.34 (1H, d, J=7.6), 8.19 (1H, s), 7.38-7.13 (10H, m), 6.26 (1H, d, J=7.6), 5.58 (1H, t), 5.31, 5.24 (1H, 2×s), 4.62 (2H, 2q), 4.60 (1H, m), 4.27 (1H, m), 2.98, 2.68 (4H, 2m), 3.0-2.0 (2H, m), 1.42 (3H, d).

N(3(S)) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(N-acetyl-O-benzyltyrosinyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53i), was obtained (76%) as a mixture of anomers: IR (KBr) 1794, 1698, 1651, 1612, 1514, 1454, 1374, 1247, 1177, 1126; ¹ H NMR (d₆ -DMSO) δ 9.34, 9.31 (2×0.5H, 2s), 8.71 (1H, 2d), 8.38 (1H, m), 8.17 (1H, d), 7.48-6.88 (19H, m), 6.08 (1H, 2d), 5.65 (0.5H, d, J=5.0), 5.40 (0.5H, s), 5.04 (2H, s), 4.68 (5.5H, m), 4.15 (0.5H, m), 3.95, 3.84 (2H, s+abq), 3.20-2.40 (4H, m), 1.78 (3H, s).

N(3(S)) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethanesulphonyl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53j), was obtained (78%) as a mixture of anomers: IR (KBr) 3344, 1792, 1691, 1647, 1599, 1566, 1454, 1365, 1150, 1121, 973; ¹ H NMR (d₆ -DMSO) δ 9.02, 8.99 (1H, 2s), 8.80 (0.5H, d, J=6.4), 8.70 (0.5H, d, J=7.4), 7.26 (15H, m), 6.00 (1H, dd), 5.63 (0.5H, d, J=5.0), 5.39 (0.5H, s), 4.68 (4.5H, m), 4.18 (0.5H, m), 3.90 (2H, m), 3.30-2.30 (6H, m).

N(3(S)) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethoxy)carbonylamino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (53k), was obtained (78%) as a mixture of anomers: IR (KBr) 3386, 1794, 1726, 1650, 1603, 1518, 1366, 1214, 699; ¹ H NMR (CDCl₃) δ 8.03 (1H, bd), 7.63, 7.61 (1H, 2×s), 7.34-7.04 (15H, m), 6.21, 6.18 (1H, 2d), 5.44 (0.5H, d, J=5.4), 5.37 (0.5H, s), 4.85, 4.83 (1H, 2d, J=11.6, 11.5), 4.61-4.48, 4.32 (4H, 2m), 4.4 (2H, t), 4.08, 4.03 (2H, 2bs), 3.07-2.78 (3H, m), 2.47-2.30 (1H, m).

N(3(S)) 2-[6-Benzyl-1,2-dihydro-2-oxo-3-(4-phenylbutyryl)amino-1-pyridyl]-N-(2-benzyloxy-5-oxotetrahydrofuran-3-yl)acetamide (531), was obtained (86%) as a colorless oil: IR (CH₂ Cl₂) 1797, 1689, 1649, 1601, 1512, 734; ¹ H NMR (CDCl₃) δ 8.42, 8.40 (1H, 2d, J=7.6), 7.35-7.07 (15H, m), 6.21, 6.19 (1H, 2d, J=7.6), 5.44 (0.5H, d), 5.37 (0.5H, s), 4.84, 4.81 (1H, 2d, J=11.7, 11.4), 4.73-4.48, 4.34 (4H, 2m), 4.05 (2H, m), 3.05-2.63, 2.46-2.30 (6H, 2m), 2.01 (2H, m).

    ______________________________________                                          ##STR109##                                                                     ##STR110##                                                                    R.sub.1          R.sub.2     R.sub.3                                           ______________________________________                                         (a)     Ph(CH.sub.2).sub.2 CO                                                                       H           (S)Me                                         (b)     Ph(CH.sub.2).sub.2 CO                                                                       CH.sub.2 Ph H                                             (c)     Ph(CH.sub.2).sub.2 CO                                                                       (CH.sub.2).sub.2 Ph                                                                        H                                             (d)     Ph(CH.sub.2).sub.2 CO                                                                       nBu         H                                             (e)     Ph(CH.sub.2).sub.2 CO                                                                       Me          H                                             (f)     Ph(CH.sub.2).sub.2 CO                                                                       Ph          H                                             (g)     Ph(CH.sub.2).sub.2 CO                                                                       H           H                                             (h)     Ph(CH.sub.2).sub.2 CO                                                                       CH.sub.2 Ph (R,S)Me                                       (i)     AcTyr        CH.sub.2 Ph H                                             (j)     Ph(CH.sub.2).sub.2 SO.sub.2                                                                 CH.sub.2 Ph H                                             (k)     Ph(CH.sub.2).sub.2 OCO                                                                      CH.sub.2 Ph H                                             (l)     Ph(CH.sub.2).sub.3 CO                                                                       CH.sub.2 Ph H                                             ______________________________________                                    

3(S), N(2(S)) 3-(2-(1,2-Dihydro-2-oxo-3-(3-phenylpropionylamino-1-pyridyl)-propionylamino)-4-oxo-butanoic acid (54a; F). A mixture of 2(S), N(3(S)) 2-[1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl]-N(2-benzyloxy-5-oxotetrahydro-furan-3-yl)propionamide 53a (1.28 g, 2.5 mmol), methanol (140 ml) ethyl acetate (60 ml) and 10% palladium on carbon (1.4 g) was stirred under an atmosphere of hydrogen. After 2.5 h more catalyst (300 mg) was added and hydrogenation continued for 1 h. The mixture was filtered through Celite™ and then refiltered through 0.2 μM nylon filter and concentrated. The residual oil triturated with a mixture of methanol and ether to afford 916 mg (87%) of colorless crystals: mp. 198°-200° C.; [α]_(D) ²⁸ -120° (0.1, CH₃ OH); IR (KBr) 3330, 1794, 1688, 1644, 1583, 1556, 1515, 1427; ¹ H NMR (CD₃ OD) δ 8.28 (1H, d), 7.35 (1H, d), 7.20 (5H, m), 6.36 (1H, t), 5.49 (1H, q), 4.59 (1H, t), 4.25 (1H, m), 2.98, 2.74 (2×2H, 2×m), 2.59 (2H, m), 1.57 (3H, d). Anal. Calcd for C₂₁ H₂₃ N₃ O₆ 0.75 H₂ O: C, 59.08; H, 5.78; N, 9.84. Found: C 59.24; H, 5.96; N, 9.84. FAB M+=414 (M+1), 297, 165, 91.

The following compounds were prepared in a similar manner:

3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid, (54b; M), was isolated (59%) as colorless crystals: mp. 115° C. (decomp);. IR (KBr) 3440, 3297, 1718, 1646, 1598, 1565, 1526, 1496, 1260; ¹ H NMR (CD₃ OD) 8.25 (1H, d, J=7.7), 7.25 (10H, m), 6.15 (1H, 2d, each J=7.7), 4.73 (2H, 2q), 4.59 (1H, m), 4.30 (1H, m), 3.95 (2H, s), 2.98 (2H, m), 2.75 (2H, m), 2.8-2.42 (2H, m). Anal. Calcd for C₂₇ H₂₇ N₃ O₆. 0.7 H₂ O: C, 64.58; H, 5.70; N, 8.37. Found: C, 64.51; H, 5.63; N, 8.38. MS FAB+ M+=490 (M+1).

3(S) 3-(1,2-Dihydro-2-oxo-6-phenethyl-3 (3-phenyl-propionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54c), was isolated (46%) as a white solid: IR (KBr) 3375, 1694, 1643, 1586, 1561, 1515, 1377, 1254, 1188, 1070; ¹ H NMR (CD₃ OD) 8.18 (1H, d, J=7.8), 7.22 (10H, m), 6.15 (1H, d, J=7.8), 4.75 (2H, s), 4.58 (1H, m), 4.30 (1H, m), 3.01-2.28 (10H, m); MS FAB+ M+=504 (M+1).

3(S) 3-(6-Butyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54d), was isolated (90%) as colorless crystals: m.p. 120°-5° C.; IR (KBr) 3315, 1784, 1679, 1644, 1589, 1561, 1556, 1520, 1415, 1379, 1186; ¹ H NMR (CD₃ OD) 8.22 (1H, d, J=7.8), 7.24 (5H, m), 6.22 (1H, d, J=7.8), 4.80 (2H, m), 4.60 (1H, s), 4.28 (1H, m), 2.98 (2H, m), 2.72 (2H, m), 2.58 (4H, m), 1.48 (4H, m), 0.97 (3H, t, J=7.1). Anal. Calcd for C₂₄ H₂₉ N₃ O₆ 0.5 H₂ O. C, 62.06; H, 6.51; N, 9.05. Found: C, 62.08; H, 6.43; N, 9.01. MS FAB+ M+=456 (M+1).

3(S) 3-(1,2-Dihydro-6-methyl-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54e), was isolated (85%) as a colorless solid: mp. 129°-138° C.; IR (KBr) 327, 3294, 1710, 1695, 1682, 1554, 1525, 1379, 1272, 1240; ¹ H (NMR (CD₃ OD) δ 8.19 (1H, d, J=7.6), 7.19 (5H, m), 6.21 (1H, d, J=7.6), 4.80 (2H, m), 4.59 (1H, m), 4.30 (1H, m), 2.98 (2H, m), 2.72 (2H, m), 2.80-2.40 (2H, m), 2.30 (3H, s). Anal. Calcd for C₂₁ H₂₂ N₃ O₆. H₂ O: C, 58.46; H, 5.84; N, 9.74. Found C: 58.82; H, 60.5; N, 9.42.

3(S) 3-(1,2-Dihydro-2-oxo-6-phenyl-3-(3-phenyl-propionyl)amino-1-pyridyl) acetylamino-4-oxobutanoic acid (54f), 73% as an off-white solid: m.p. 140° C. (decomp). [α]_(D) ²⁴ =-8.5° (c 0.1, MeOH). IR (KBr) 3302, 1796, 1726, 1679, 1643, 1590, 1560, 1516, 1490, 1449, 1420, 1398, 1376, 1231; ¹ H NMR (CD₃ OD) δ 8.36 (1H, d), 7.49-7.14 (10H, m), 6.27 (1H, dd), 4.54 (3H, m), 4.30 (1H, m), 3.0, 2.73 (2×2H, 2×m), 2.7-2.29 (2H, m).

3(S) 3-(1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54g; G), was isolated (73%) as a foam: mp. 140°-5° C. (decomp); IR (KBr) 3352, 3314, 1719, 1700, 1668, 1649, 1600, 1559, 1514, 1379, 1261; ¹ H NMR (CD₃ OD) δ 8.32 (1H, d, J=7.5), 7.19 (6H, m), 6.34 (1H, t), 5.1-4.6 (3H, m), 4.32 (1H, m), 2.7 (6H, m). Anal. Calcd for C₂₀ H₂₁ N₃ O₆. 0.6H₂ O: C, 58.50, H, 5.45, N, 10.24. Found: C, 58.43, H, 5.35, N. 9.85. MS FAB+ M+=400 (M+1).

3(S), N(2(R,S)) 3-(2-(6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)propionylamino)-4-oxobutanoic acid (54h), was obtained (69%) as a colorless foam: m.p. 120° C.; [α]_(D) ²⁰ -16.0° (C, 0.11, CH₂ Cl₂). IR (KBr) 3315, 1783, 1727, 1666, 1644, 1599, 1564, 1517, 1454, 1379; ¹ H NMR (CD₃ OD) δ 8.23 (1H, m), 7.27 (10H, m), 6.28 (1H, m), 4.84 (1H, m), 4.53 (1H, m), 4.22 (1H, m), 4.10 (2H, m), 2.96 (2H, m), 2.72 (2H, m), 2.39 (2H, m), 1.21 (3H, m). Anal. Calcd for C₂₈ H₂₉ N₃ O₆. 1.25H₂ O: C, 63.93, H, 6.03, N, 7.99. Found: C, 63.98, H, 5.85, N, 7.86. MS FAB (+) M+=504 (M+1).

3(S) 3-(3-(2-Acetyl-L-tyrosinyl)amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl)acetylamino-4-oxobutanoic acid (54i), was isolated (79%) as colorless crystals: mp. 193°-6° C. (decomp.); IR (KBr) 3284, 1644, 1599, 1565, 1519, 1455, 1429, 1407, 1375, 1267, 1251; ¹ H NMR (d₆ -DMSO/CDCl₃) δ 8.16 (1H, d, J=7.7), 7.26 (5H, m), 7.03 (2H, d, J=8.4), 6.61 (2H, d, J=8.4), 6.03 (1H, d, J=7.7), 4.58 (3H, m), 4.44 (1H, m), 4.13 (1H, m), 3.84 (2H, s), 3.07-2.30 (4H, m). Anal. Calcd for C₂₉ H₃₀ N₄ O₈.2H₂ O: C, 58.19; H, 5.72; N, 9.36. Found: C, 58.11; H, 5.63; N, 9.29. MS FAB+ M+=563 (M+1).

3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethane-sulphonyl)amino-1-pydridyl)acetylamino-4-oxobutanoic acid (54j), was isolated (85%) as a colorless solid: mp. 102°-5° C.; [α]_(D) ²³ -9.9° (c 0.1, MeOH); IR (KBr) 3452, 3328, 3155, 1719, 1679, 1645, 1594, 1567, 1453, 1425, 1357, 1307, 1225, 1148, 1132; ¹ H NMR (CD₃ OD) δ 7.52 (1H, d, J=7.6), 7.33 (10H, m), 6.12 (1H, d, J=7.6), 4.73 (2H, m), 4.58 (1H, d, J=3.7), 4.34 (1H, m), 3.97 (2H, s), 3.29 (2H, m), 3.08 (2H, m), 2.75-2.37 (2H, m). Anal. Calcd for C₂₆ H₂₇ N₃ O₇ S. 1.7H₂ O: C, 56.14; H, 5.51; N, 7.55. Found: C, 56.20; H, 5.49; N, 7.29. MS FAB+ M+=526 (M+1).

3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethoxy)carbonylamino-1-pyridyl)acetylamino-4-oxobutanoic acid (54k), was isolated (54%) as an off-white solid: mp. 84°-86° C.; IR (KBr) 3373-3310, 1787, 1726, 1691, 1649, 1599, 1567, 1517, 1367, 1215; ¹ H NMR (CD₃ OD) δ 7.93 (1H, bd, J=7.4), 7.37-7.18 (10H, m), 6.15 (1H, d, J=7.4), 4.77 (1H, d, J=3.7), 4.67 and 4.58 (2H, 2m), 4.35 (2H, t, J=6.9), 4.35 (1H, m), 3.94 (2H, s), 2.98 (2H, t, J=6.9), 2.76-2.39 (2H, m).

3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(4-phenylbutyryl)carbonylamino-1-pyridyl)acetylamino-4-oxobutanoic acid (54l), was isolated (50%) as a white solid: mp. 89°-93° C.; IR (KBr) 3369-3302, 1678, 1645, 1594, 1565, 1517, 1379, 1258; ¹ H NMR (d₄ -methanol) δ 8.25 (1H, d, J=7.6), 7.37-7.18 (10H, m), 6.15 (1H, d, J=7.4), 4.74 (2H, m), 4.60 (1H, m), 4.30 (1H, m), 3.97 (2H, s), 2.76-2.37 (2H, m), 2.67 (2H, t), 2.45 (2H, t), 1.98 (2H, m). Anal. Calcd for C₂₈ H₂₉ N₃ O₆. 1.5H₂ O: C, 63.39; H, 6.08; N, 7.92. Found C: 63.69; H, 5.74; N, 7.83. ##STR111##

t-Butyl N-2-(3-benzyloxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl)acetyl-3-amino-5-(2,6-dichloro-benzoyloxy)-4-oxo-pentanoate (56a). The acetic acid (55a) (WO 93 21213) in THF (2 ml) was stirred at room temperature and treated with 1-hydroxybenzotriazole (60 mg, 0.448 mmol) and dimethylaminopropyl-3-ethylcarbodiimide hydrochloride (47 mg, 0.246 mmol). After 5 mins water (2 drops) was added and stirring continued for 20 minutes. Bis(triphenylphosphine) palladium II chloride (6 mg) was added followed by a solution of t-butyl 3-(allyloxycarbonylamino)-4-oxo-5-(2,6-dichlorobenzoyl-oxy)pentanoate (WO 93 16710) (103 mg, 0.224 mmol) in THF (1 ml). Tributyltin hydride (0.09 ml, 0.336 mmol) was added dropwise over 1 hour at room temperature. The mixture was stirred for a further 3 hours and poured onto ethyl acetate, washed with 1M HCl, aqueous NaHCO₃, brine, dried over MgSO₄ and concentrated in vacuo. The residue was triturated with pentane and the supernatant discarded. The remaining solid was purified by flash chromatography (50% ethyl acetate/hexane) to afford the title compound 92 mg (63%) as a colorless oil: [α]_(D) ²⁶ -29.6° (c 1.1, CH₂ Cl₂); IR (film) 3377, 3365, 3332, 3312, 1733, 1691, 1650, 1599, 1515, 1366, 1261, 1153, 1068, 747; ¹ H NMR (CDCl₃) δ 8.09 (1H, d, J=6.8), 7.84 (1H, s), 7.58 (1H, d, J=8.3), 7.33 (8H, m), 7.02 (1H, dd, J=6.9, 1.7), 6.33 (1H, t, J=7.2), 5.20 (2H, s), 5.12 (2H, m), 4.89 (1H, dt), 4.65 (2H, m), 2.80 (2H, m), 1.38 (9H, s).

t-Butyl N-2-(6-benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetyl-3-amino-5-(2,6-dichlorobenzyloxy)-4-oxo-pentanoate (56b), was prepared by the method described for (56a) which afforded the title compound (66%) as a colorless oil: IR (film) 3364, 3313, 1738, 1688, 1648, 1600, 1566, 1514, 1433, 1369, 1254, 1152; ¹ H NMR (CDCl₃) δ 8.40 (1H, d, J 7.6), 8.30 (1H, s), 7.28 (13H, m), 6.20 (1H, d, J=7.6), 5.12 (2H, q), 4.86 (1H, m), 4.65 (2H, q), 4.06 (2H, s), 3.07-2.61 (6H, m), 1.39 (9H, s). ##STR112##

N-2(3-Benzyloxycarbonylamino-1,2-dihydro-2-oxo-1-pyridyl)acetyl-3-amino-5-(2,6-dichlorobenzoyloxy)-4-oxo-pentanoic acid (57a; O). The ester (56a) (210 mg, 0.356 mmol) in dichloromethane (0.5 ml) was cooled to 0° C. and treated with trifluoroacetic acid (0.5 ml), stirred and warmed to 20° C. over 30 minutes. The solution was evaporated to dryness under reduced pressure, redissolved in dichloromethane and concentrated (×3). The residue was triturated with ethyl acetate and diluted with ether to afford the title compound 162 mg (85%) as a colorless solid: m.p. 165°-8° C. (decomposition); [α]_(D) ²³ -38.8° (c 0.1, CH₃ OH); IR (KBr) 3332, 3275, 1723, 1658, 1649, 1597, 1581, 1562, 1526, 1432, 1385, 1258, 1218, 1206; ¹ H NMR (D₆ -DMSO) δ 8.96 (1H, d, J=7.3), 8.34 (1H, s), 7.85 (1H, dd, J=7.3), 7.58 (3H, m), 7.35 (5H, m), 6.29 (1H, t, J=7.3), 5.26 (2H, m), 5.15 (2H, s), 4.69 (3H, m), 2.75 (2H, m). Anal. Calcd. C₂₇ H₂₃ N₃ O₉ Cl₂ : C, 53.66; H, 3.84; N, 6.95. Found: C, 53.36; H, 3.90; N, 6.81. M.S. (+FAB); 604 (M⁺ +1), 285, 241, 195, 173, 149, 91.

N-2-(6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetyl-3-amino-5-(2,6-dichloro-benzoyloxy)-4-oxo-pentanoic acid (57b; P), was prepared by the method described for 57a which afforded the title compound (78%) as colorless crystals: m.p. 116°-120° C. (decomposition); [α]_(D) ²⁶ -41.1° (c 0.1, CH₃ OH); IR (KBr) 3299, 1739, 1715, 1689, 1666, 1645, 1598, 1563, 1518, 1432, 1209, 1151; ¹ H NMR (D₆ -DMSO) δ 9.24 (1H, s), 8.88 (1H, d, J=7.6), 8.18 (1H, d, J=7.7), 7.60 (3H, m), 7.26 (10H, m), 6.06 (1H, d, J=7.7), 5.23 (2H, ABq), 4.69 (3H, m), 3.93 (2H, s), 2.78 (6H, m). Anal. Calcd. for C₃₅ H₃₁ N₃ O₈ Cl₂. H₂ O: C, 59.16; H, 4.68; N, 5.91. Found: C, 59.38; H, 4.53; N, 5.84. M.S. (+FAB); 694, (Cl=35, 37), (M⁺ +1); 692 (Cl=35, 35), (M⁺ +1). ##STR113##

(3S, 4RS) t-Butyl N-(benzyloxycarbonyl)-3-amino-4-(2-benzoxazolyl)-4-hydroxy-butanoate (59). To a stirred solution of benzoxazole (250.2 mg, 2.1 mmol) in anhydrous THF (10.5 ml) at -78° C. under N₂ was added 2.3M n-butyl lithium in hexanes (0.96 ml, 2.2 mmol) dropwise. After stirring at -78° C. for 20 min, dry MgBr₂ OEt₂ (594.0 mg, 2.3 mmol) was added as a solid. The resulting heterogeneous mixture was warmed to -45° C. and stirred for 15 min. The reaction mixture was then recooled to -78° C. and a solution of aldehyde 58 (Graybill et al., Int. J. Peptide Protein Res., 44, pp. 173-182 (1993)) (644.6 mg, 2.1 mmol) in THF (10.5 ml) was added dropwise. The reaction was stirred at -78° C. for 30 min, warmed to 0° C. for 1 h, and then stirred at room temperature for 16 h. The reaction was quenched with 5% sodium bicarbonate (2.0 ml) and the THF was removed in vacuo. The resulting aqueous residue was extracted four times with methylene chloride. The combined extracts were washed with brine, dried (MgSO₄), filtered and reduced in vacuo to give 880.0 mg of crude product. Flash chromatography (45:55 ethyl acetate/hexane) afforded 567.2 mg (63%) of the title compound, an oil, as a mixture of diastereoisomers at C-4. IR (film) 3324, 2976, 1726, 1517, 1455, 1368, 1243, 1159, 1048, 747; ¹ H NMR (CDCl₃) δ 7.71-7.64 (1H, m), 7.52-7.48 (1H, m), 7.37-7.20 (7H, m), 5.91 (1H, brd, J=9.0), 5.79 (1H, d, J=9.0), 5.41-4.78 (4H, m), 4.75-4.54 (1H, m), 2.91-2.51 (2H, m), 1.42 (9H, s), 1.37 (9H, s).

(3S, 4RS) t-Butyl-amino-4-(2-benzoxazolyl)-4-hydroxybutanoate (60). A solution of the ester 59 (189.0 mg, 0.44 mmol) in ethanol (5.0 ml) was treated with 10% Palladium on carbon (20.5 mg) and stirred under an atmosphere of H₂ for 21 h. The mixture was filtered through Celite®, and the solvent was evaporated to afford 125.0 mg (98%) of crude amine 60 as an oil. This was used without further purification. ¹ H NMR (CDCl₃) δ 7.73-7.64 (1H, m), 7.51-7.42 (1H, m), 7.35-7.22 (2H, m), 6.48 (3H, brs), 5.58 (1H, d, J=3.0), 5.27 (1H, d, J=6.5), 4.23-4.05 (1H, m), 2.92-2.63 (2H, m), 1.36 (9H, s), 1.33 (9H, s).

(3S, 4RS) t-Butyl N-(N-benzyloxycarbonyl-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-benzoxazolyl)-4-hydroxybutanoate (61). A solution of the amine 60 (261.4 mg, 0.89 mmol), Z-Val-Ala-OH (286.9 mg, 0.89 mmol) (prepared by standard peptide synthetic procedures) and hydroxybenzotriazole (120.3 mg, 0.89 mmol) in DMF (3.0 ml) at 0° C. was treated with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (179.2 mg, 0.93 mmol). The reaction was warmed to room temperature and stirred for 16 h. The reaction was diluted with ethyl acetate and washed twice with 1M sodium hydrogensulphate, twice with saturated sodium bicarbonate, then water, and brine. The organic layer was dried (MgSO₄), filtered and reduced in vacuo to afford 494.8 mg of crude product. Flash chromatography (95:5 methylene chloride/methanol) gave 480.9 mg (91%) of the title compound as a yellow solid: mp. 81°-83° C.; IR (KBr) 3312, 2974, 1723, 1709, 1529, 1455, 1368, 1243, 1156, 747; ¹ H NMR (CDCl₃) δ 7.79 (0.5H, d, J=8.0), 7.73-7.20 (9.5H, m), 6.15 (1H, t, J=8.5), 5.74 (0.5H, brd, J=5.5), 5.45 (1H, brd, J=7.5), 5.28-5.20 (0.5H, m), 4.82-4.11 (3.5H, m), 4.78-4.55 (1H, m), 4.40-4.22 (1H, m), 2.95-2.51 (2H, m), 2.12-1.95 (1H, m), 1.45-1.32 (12H, m), 1.11-0.81 (6H, m), ¹³ C NMR (CDCl₃) δ 173.14, 172.94, 171.82, 171.03, 170.78, 165.98, 165.45, 157.29, 157.17, 151.23, 151.10, 140.92, 140.82, 136.83, 136.79, 128.91, 128.52, 125.75, 124.97, 120.60, 120.40, 111.38, 81.82, 81.68, 70.27, 68.97, 67.44, 60.43, 50.74, 50.55, 49.18, 49.07, 36.87, 36.57, 32.37, 28.51, 19.88, 19.80, 18.53. Anal. Calcd. for C₃₁ H₄₀ N₄ O₈. H₂ O: C, 60.57; H, 6.89; N, 9.11. Found: C, 60.84; H, 6.64; N, 9.09. M.S. (+FAB); 597 (M⁺ +1); 541, 91.

(3S) t-Butyl N-(N-benzyloxycarbonyl-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-benzoxazolyl)-4-oxobutanoate (62). The alcohol 61 (100.3 mg, 0.17 mmol) was dissolved in methylene chloride (2.0 ml) and Dess-Martin reagent (142.6 mg, 0.34 mmol) was added (Ireland et al., J. Org. Chem., 58, p. 2899 (1993); Dess et al., J. Org. Chem., 48, pp. 4155-4156 (1983)). The resulting mixture was stirred for 22 min and then partitioned between saturated sodium thiosulphate: saturated sodium bicarbonate (1:1, 10 ml), and ethyl acetate (10 ml). The resulting organic phase was washed with saturated sodium thiosulphatesaturated sodium bicarbonate (1:1), saturated sodium bicarbonate and brine. The organic phase was dried (MgSO₄), filtered and reduced in vacuo to give 111.3 mg of crude product. Flash chromatography (95:5 methylene chloride/methanol) afforded 97.3 mg (96%) of the title compound as an oil: [α]_(D) ²³ -11.74° (c 0.95, CH₂ Cl₂); IR (CH₂ Cl₂) 3419, 2974, 1721, 1677, 1501, 1369, 1221, 1156; ¹ H NMR (CDCl₃) δ 7.89-7.84 (1H, m), 7.73-7.22 (10H, m), 5.98 (1H, d, J=9.0), 5.72 (1H, m), 5.10 (2H, q, J=12.5), 4.73 (2H, m), 4.20 (1H, dd, J=7.0, 8.5), 3.30 (1H, dd, J=5.0, 16.5), 3.03 (1H, dd, J=5.5, 16.5), 2.18-1.97 (1H, m), 1.39 (3H, d, J=7.0), 1.34 (9H, s), 0.93 (3H, d, J=6.0), 0.90 (3H, d, J=6.0), ¹³ C NMR (CDCl₃) δ 186.46, 172.73, 171.90, 170.13, 157.17, 156.28, 151.16, 140.99, 136.99, 129.39, 129.08, 128.66, 128.59, 126.49, 123.06, 112.55, 82.73, 67.60, 60.84, 53.75, 49.41, 38.58, 32.05, 28.52, 19.85, 19.32, 18.51. M.S. (+FAB); 595 (M⁺ +1); 539, 91.

(3S) N-(N-Benzyloxycarbonyl-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-benzoxazolyl)-4-oxobutanoate (63; Q). A solution of the ester 62 (95.0 mg, 0.16 mmol) in a 1:1 mixture of methylene chloride and trifluoroacetic acid (10.0 ml) was stirred for 1 h under a dry atmosphere of N₂. The solution was then reduced in vacuo, taken up in ether and reduced again. This process was repeated six times to afford the crude product as an off white solid. Flash chromatography (95:5 methylene chloride/methanol) gave 60.0 mg (69%) of the title compound as a white solid. The product existed as a mixture of three isomers in CD₃ OD, consisting of the ketone form (one isomer, c 44%), and its acycloxy ketal form (two isomers at C-4, c. 56%): m.p. 156°-159° C. [α]_(D) ²⁶ -45.6° (c 0.13, methanol); IR (KBr) 3440, 2967, 1713, 1703, 1638, 1531, 1427; ¹ H NMR (CD₃ OD) δ 7.93-7.24 (9H, m), 5.59 (1H, brt), 5.16-5.00 (2H, m), 5.0-4.78 (1H, m), 4.50-4.22 (1H, m), 3.95-3.81 (1H, m), 3.11 (2H, d, J=6.5), 3.05-2.92 (1H, m), 2.70-2.39 (1H, m), 2.08-1.89 (1H, m), 1.19-0.78 (9H, m). Anal. Calcd. for C₂₇ H₃₀ N₄ O₈. 0.5H₂ O: C, 59.22; H, 5.71; N, 10.23. Found: C, 59.48, H, 5.36, N, 10.17. M.S. (+FAB); 539 (M⁺ +1), 91. ##STR114## (a) R¹ =OCH₃, R² =H (b) R¹ =H, R² =OCH₃

7-Methoxybenzoxazole (65a). A mixture of 2-nitro-6-methoxyphenol (2.62 g, 15.5 mmol) (EP 333176) and 10% Palladium on carbon (130 mg) in ethanol (50.0 ml) was stirred under an atmosphere of H₂ for 75 min. The mixture was filtered through Celite® then immediately treated with p-toluenesulphonic acid (32.0 mg) and triethylorthoformate (6.45 ml, 38.8 mmol) then heated under reflux under an atmosphere of N₂. After 20 h p-toluenesulphonic acid (30.0 mg) and triethylorthoformate (6.45 ml, 38.8 mmol) were added. After a total of 44 h heating, the reaction was allowed to cool and reduced in vacuo. The resulting residue was purified by flash chromatography (25:75 ethyl acetate/hexane) to give 1.97 g (85%) of the title compound as a yellow solid: m.p. 28°-31° C.; IR (film) 1629, 1497, 1434, 1285, 1097; ¹ H NMR (CDCl₃) δ 8.09 (1H, s), 7.40 (1H, d, J=8.0), 7.28 (1H, t, J=8.0), 6.89 (1H, d, J=8.0), 4.02 (3H, s); ¹³ C NMR (CDCl₃) δ 152.84, 145.82, 142.50, 139.99, 125.75, 113.42, 108.80, 56.97. Anal. Calcd. for C₈ H₇ N₁ O₂. 0.1H₂ O: C, 63.65; H, 4.81; N, 9.29. Found: C, 63.43, H, 4.88, N, 9.05. M.S. (+FAB); 150 (M⁺ +1).

4-Methoxybenzoxazole (65b). To a suspension of 4-hydroxybenzoxazole (2.00 g, 14.8 mmol) (Musser et al., J. Med. Chem., 30, pp. 62-67 (1987)) in acetone (80.0 ml) was added dried K₂ CO₃ (2.25 g, 16.3 mmol) followed by iodomethane (1.38 ml, 22.2 mmol). The reaction was heated under reflux under N₂ for 4.5 h, then filtered and reduced in vacuo to afford the crude product. The resulting residue was purified by flash chromatography (25:75 ethyl acetate/hexane) to give 2.0 g (91%) of the title compound as a white crystalline solid: m.p. 72°-74° C.; IR (KBr) 3089, 1619, 1610, 1503, 1496, 1322, 1275, 1090, 1071, 780, 741; ¹ H NMR (CDCl₃) δ 8.02 (1H, s), 7.32 (1H, t, J=8.0), 7.18 (1H, d, J=8.0), 6.81 (1H, d, J=8.0), 4.04 (3H, s). Anal. Calcd. for C₈ H₇ NO₂ : C, 64.42; H, 4.73; N, 9.39. Found: C, 64.40; H, 4.84; N, 9.31; m/z (EI) 149 (M⁺ +1, 100%).

(3S, 4RS) t-Butyl N-(allyloxycarbonyl)-3-amino-4-hydroxy-4-(2-(7-methoxybenzoxazolyl))butanoate (66a). To a stirred solution of 7-methoxybenzoxazole 65a (548.6 mg, 3.68 mmol) in anhydrous THF (18.5 ml) at -78° C. under N₂ was added 1.56M n-butyl lithium in hexanes (2.47 ml, 3.86 mmol) dropwise, to produce a yellow colored solution. After stirring at -78° C. for 20 min, dry MgBr₂ OEt₂ (1.045 g, 4.05 mmol) was added as a solid. The resulting heterogeneous mixture was warmed to -45° C. and stirred for 15 min. The reaction mixture was then recooled to -78° C. and a solution of (S)-Alloc-Asp(t-Bu)H^(1b) (946.4 mg, 3.68 mmol) in THF (18.5 ml) was added dropwise. The reaction was stirred at -78° C. for 30 min, warmed to 0° C. and stirred for 1 h. The resulting homogeneous reaction was warmed to room temperature and stirred for 16 h. The reaction was quenched with 5% sodium bicarbonate (3.5 ml) then THF was removed in vacuo. The resulting aqueous residue was extracted with methylene chloride (×6). The combined extracts were washed with brine, dried (MgSO₄), filtered and reduced in vacuo to give 1.8 g of crude product. Flash chromatography (40:60 ethyl acetate/hexane) gave 1.21 g (81%) of the title compound, an oil, as a mixture of diastereoisomers at C-4: IR (CH₂ Cl₂) 3425, 2983, 1725, 1504, 1290, 1157, 1101; ¹ H NMR (CDCl₃) δ 7.35-7.19 (2H, m), 6.89-6.81 (1H, m), 6.00-5.57 (2H, m), 5.32-5.05 (3H, m), 4.68-4.35 (3H, m), 4.01 (3H, s), 2.86-2.59 (2H, m), 1.45 (9H, s), 1.41 (9H, s); ¹³ C NMR (CDCl₃) δ 171.18, 171.09, 165.80, 165.30, 156.71, 156.60, 145.65, 142.76, 142.71, 140.82, 140.72, 133.23, 125.81, 125.72, 118.41, 118.21, 113.07, 112.87, 108.95, 82.16, 70.28, 69.98, 66.52, 66.39, 57.03, 52.57, 52.29, 37.83, 36.86, 28.65. Anal. Calcd. for C₁₀ H₂₆ N₂ O₇. 0.6H₂ O: C, 57.57; H, 6.57; N, 6.72. Found: C, 57.49, H, 6.34, N, 6.60. M.S. (+FAB); 407 (M⁺ +1) ; 351, 307, 154.

(3S, 4RS) t-Butyl N-(allyloxycarbonyl)-3-amino-4-hydroxy-4-(2-(4-methoxybenzoxazolyl))butanoate (66b), was prepared according to the method described for 66a which afforded 1.29 g (26%, 68% based on recovered starting material) of the title compound as an oil and as a mixture of diastereoisomers at C-4: IR (CH₂ Cl₂) 3400, 1725, 1625, 1505, 1369, 1354, 1281, 1263, 1226, 1158, 1092, 1048; ¹ H NMR (CDCl₃) δ 7.34-7.24 (1H, m), 7.16 (1H, d, J=8.2), 6.79 (1H, d, J=7.9), 6.00-5.50 (2H, m), 5.30-5.05 (3H, m), 4.70-4.35 (4H, m), 4.02 (3H, s), 2.90-2.45 (2H, m), 1.45-1.41 (9H, 2×s). Anal. Calcd. for C₂₀ H₂₆ N₂ O₇. 0.4H₂ O: C, 58.07; H, 6.53; N, 6.77. Found: C, 58.09; H, 6.41; N, 6.63. M.S. (+FAB); 407 (M⁺ +1, 88%); 351 (100).

(3S, 4RS) t-Butyl N-(N-acetyl-(S)-(O-tert-butyl-tyrosinyl)-(S)-valinyl-(S)-alaninyl)-3-amino-4-hydroxy-4-(2-(7-methoxybenzoxazolyl))butanoate (67a). To a stirred solution of the benzoxazole 66a (481.9 mg, 1.19 mmol) and Ac-Tyr(tBu)-Val-Ala-OH (586.3 mg, 1.30 mmol) in methylene chloride (3.5 ml) and DMF (3.5 ml) was added bis(triphenylphosphine) palladium (II) chloride (18.0 mg), followed by tributyltinhydride (0.80 ml, 2.96 mmol) dropwise. Hydroxybenzotriazole (320.4 mg, 2.37 mmol) was added and the mixture cooled to 0° C. 1-Ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (278.2 mg, 1.42 mmol) was added and the mixture was allowed to warm to room temperature and stirred for 16.5 h. The reaction was diluted with ethyl acetate and washed twice with 1M sodium hydrogensulphate, twice with saturated sodium bicarbonate, water, and brine. The organic layer was dried (MgSO₄), filtered and reduced in vacuo to yield 2.0 g of crude product. Flash chromatography (95:5 methylene chloride/methanol) gave 844.0 mg (94%) of the title compound as a white solid: m.p. 205° C.; IR (KBr) 3399, 3304, 2977, 1729, 1643, 1506, 1367, 1290, 1161; ¹ H NMR (d₆ -DMSO) δ 8.24-7.78 (4H, m), 7.43-7.32 (2H, m), 7.23 (2H, d, J=8.5), 7.16-7.07 (1H, m), 6.93 (2H, d, J=8.5), 6.52, 6.40 (1H, 2×d, J=5.5, J=5.0), 5.03, 4.78-4.49, 4.45-4.16 (5H, brt, 2×m), 4.05, 4.04 (3H, 2×s), 3.08-2.35 (14H, m), 2.11-1.89 (1H, m), 1.83 (3H, s), 1.49-1.32, 1.15, 1.0-0.81 (27H, s, 2×m, J=7.0); ¹³ C NMR (d₆ -DMSO) δ 175.55, 175.18, 173.88, 173.75, 173.05, 169.23, 157.28, 148.55, 146.16, 143.21, 136.63, 133.55, 128.87, 127.17, 115.78, 111.92, 84.02, 81.50, 71.40, 61.15, 60.05, 57.79, 53.39, 51.62, 43.76, 40.52, 34.58, 32.52, 31.60, 26.35, 23.11, 22.71, 21.76. Anal. Calcd. for C₃₉ H₅₅ N₅ O₁₀. 0.5H₂ O: C, 61.40; H, 7.40; N, 9.18. Found: C, 61.43; H, 7.31; N, 9.07. M.S. (+FAB); 754 (M⁺ +1); 698, 338, 267.

(3S, 4RS) t-Butyl N-(N-acetyl-(S)-(O-tert-butyl-tyrosinyl)-(S)-valinyl-(S)-alaninyl)-3-amino-4-hydroxy-4-(2-(4-methoxybenzoxazolyl))butanoate (67b), was prepared according to the method described for 67a which afforded 1.05 g (94%) of the title compound as a fine white powder: m.p. 210°-21° C. (dec); IR (KBr) 3284, 2977, 1736, 1691, 1632, 1536, 1505, 1452, 1392, 1367, 1258, 1236, 1161, 1091; ¹ H NMR (d₆ -DMSO) δ 8.20-7.75 (4H, m), 7.40-7.10 (4H, m), 7.00-6.80 (3H, m), 6.45, 6.34 (1H, 2×d, J=5.3, J=5.0), 5.00-4.10 (5H, m), 4.00, 3.99 (3H, 2×s), 3.00-2.25 (4H, m), 1.95 (1H, m), 1.78 (3H, s), 1.39-0.80 (27H, m). Anal. Calcd. for C₃₉ H₅₅ N₅ O₁₀. 0.5H₂ O: C, 61.40; H, 7.40; N, 9.18. Found: C, 61.58; H, 7.38; N, 8.91. M.S. (+FAB); 754 (M⁺ +1, 30%); 72 (100).

(3S) t-Butyl N-(N-acetyl-(S)-(O-tert-butyl-tyrosinyl)-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-(7-methoxybenzoxazolyl))-4-oxobutanoate (68a). The Dess-Martin reagent (1.082 g, 2.55 mmol) (Ireland et al., J, Org. Chem., 58, p. 2899 (1993); Dess et al., J. Org. Chem., 48, pp. 4155-4156 (1983)) was added to a stirred suspension of the alcohol 67a (641.0 mg, 0.85 mmol) in methylene chloride (46.0 ml). The resulting mixture was stirred for 1 h before being partitioned between saturated sodium thiosulphate: saturated sodium bicarbonate (1:1, 86.0 ml) and ethyl acetate (86.0 ml). The resultant organic phase was washed in turn with saturated sodium thiosulphate: saturated sodium bicarbonate (1:1), saturated sodium bicarbonate, and brine. The organic phase was dried (MgSO₄), filtered and reduced in vacuo to give 660.0 mg of crude product. Flash chromatography (94:6 methylene chloride/methanol) gave 636.0 mg (100%) of the title compound as a white solid: m.p. 209° C.; [α]_(D) ²⁴ -21.8° (c 0.16, methanol); IR (KBr) 3395, 3294, 2977, 1722, 1641, 1535, 1505, 1161; ¹ H NMR (CDCl₃) δ 8.43-8.16 (1H, m), 7.97-7.62 (2H, m), 7.49-7.14 (3H, m), 7.08-6.95 (3H, m), 6.89-6.73 (2H, m), 5.81-5.68 (1H, m), 5.16-4.86 (2H, m), 4.53 (1H, brt), 4.03 (3H, s), 3.16-2.84 (4H, m), 2.11-1.84 (4H, m), 1.46-1.14 (21H, m), 0.92-0.78 (6H, m); ¹³ C NMR (CDCl₃) δ 186.28, 173.39, 171.90, 171.19, 171.03, 169.89, 156.43, 154.75, 146.32, 142.88, 140.98, 132.31, 130.54, 126.98, 124.73, 114.95, 111.42, 82.44, 78.71, 58.92, 57.20, 54.91, 53.47, 48.77, 39.43, 38.15, 32.79, 29.44, 28.60, 23.55, 20.27, 19.7.0, 19.34. M.S. (+FAB); 752 (M⁺ +1); 696, 336, 265.

(3S) t-Butyl N-(N-acetyl-(S)-(O)-tert-butyl-tyrosinyl)-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-(4-methoxybenzoxazolyl))-4-oxobutanoate (68b), was prepared according to the method described for the ketone 68a which afforded 420 mg (55%) of the title compound as a white solid: m.p. 211°-213° C. (dec); [α]_(D) ²⁴ -23.9° (c 0.82, methanol); IR (KBr) 3277, 3075, 1723, 1690, 1632, 1530, 1506, 1392, 1366, 1269, 1234, 1160, 1094; ¹ H NMR (CDCl₃) δ 8.15 (1H, brs), 7.7 (2H, brs), 7.46 (1H, t, J=8.3), 7.24 (2H, d, J=8.3), 7.10 (1H, brs), 7.03 (2H, d, J=8.3), 6.83 (3H, m), 5.74 (1H, q, J=6.9), 5.00 (2H, m), 4.51 (1H, t, J=7.0), 4.07 (3H, s), 3.20-2.95 (4H, m), 2.00 (4H, m), 1.42 (3H, d, J=6.8), 1.35 (9H, s), 1.23 (9H, s), 0.86 (6H, d, J=6.7). M.S. (+FAB); 752 (M⁺ +1, 7%); 72 (100).

(3S) N-(N-Acetyl-(S)-tyrosinyl-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-(7-methoxybenzoxazolyl))-4-oxobutanoate (69a; R). A solution of the ester 68a (600.0 mg, 0.80 mmol) in a 1:1 mixture of methylene chloride and trifluoroacetic acid (65.0 ml) was stirred for 1 h under a dry atmosphere of N₂. The solution was then reduced in vacuo, taken up in ether and reduced again. This process was repeated six times to afford the crude product as an off white solid. Flash chromatography (gradient 95:5 to 80:20 methylene chloride/methanol) gave 420.8 mg (83%) of the title compound as a .hygroscopic white solid. The product existed as a mixture of three isomers in CD₃ OD, consisting of the keto form (c 50%), and its acycloxy keto form (two isomers at C-4, c 50%): m.p. decomposes above 150° C.; [α]_(D) ²⁴ -33.2° (c 0.17, methanol); IR (KBr) 3300, 1715, 1658, 1650, 1531, 1517, 1204; ¹ H NMR (CD₃ OD) δ 7.46-7.19 (2H, m), 7.16-6.91 (3H, m), 6.70-6.59 (2H, m), 5.62-5.49 (1H, m), 5.00-4.72 (1H, obscurred m), 4.69-4.51 (1H, m), 4.49-4.08 (2H, m), 4.05-3.89 (3H, m), 3.16-2.47 (4H, m), 2.05-1.78 (4H, m), 1.41-1.11, 1.05-0.70 (9H, 2×m). Anal. Calcd. for C₃₁ H₃₇ N₅ O₁₀. 3H₂ O: C, 53.67; H, 6.25; N, 10.10. Found: C, 53.76; H, 5.56; N, 10.28. M.S. (+FAB); 640 (M⁺ +1); 435, 147.

(3S) t-Butyl N-(N-acetyl-(S)-tyrosinyl-(S)-valinyl-(S)-alaninyl)-3-amino-4-(2-(4-methoxybenzoxazolyl))-4-oxobutanoate (69b; S), was prepared according to the method described for the acid 69a which afforded the hygroscopic title compound 252 mg (96%). The product existed as a mixture of three isomers in CD₃ OD, consisting of the keto form, and its acycloxy ketal form (two isomers at C-4). The product existed as a single isomer in d-6 DMSO: m.p. 200°-203° C. (dec.); [α]_(D) ²⁴ -38.0° (c 0.23, methanol); IR (KBr) 3289, 2968, 1718, 1713, 1658, 1634, 1548, 1517, 1506, 1461, 1453, 1393, 1369, 1268, 1228, 1174, 1092; ¹ H NMR (D₆ -DMSO) δ 9.20 (1H, brs), 8.71 (1H, d, J=6.2), 8.10 (2H, m), 7.83 (1H, d, J=8.7), 7.61 (1H, t, J=8.2), 7.46 (1H, d, J=8.2), 7.08 (3H, m), 6.65 (2H, d, J=8.3), 5.50 (1H, q, J=6.5), 4.50 (1H, m), 4.37 (1H, m), 4.20 (1H, m), 4.05 (3H, s), 3.09-2.77 (4H, m), 1.94 (1H, m), 1.79 (3H, s), 1.23 (3H, d, J=7.0), 0.82 (6H, m). Anal. Calcd. for C₃₁ H₃₇ N₅ O₁₀. 1.5H₂ O: C, 55.85; H, 6.05; N, 10.51. Found: C, 55.21; H, 5.69; N, 10.13. M.S. (+FAB); 640 (M⁺ +1, 22%); 107 (100). ##STR115##

3S) t-Butyl N-(allyloxycarbonyl)-3-amino-4-oxo-5-(1,2-dioxo-2-phenylethyloxy)-pentanoate (80). Potassium fluoride (792 mg, 13.6 mmol) and then benzoyl formic acid (1.02 g, 6.82 mmol) were added to a stirred solution of (3S) t-butyl N-(allyloxycarbonyl)-3-amino-5-bromo-4-oxo-pentanoate (WO 93 16710) (2.17 g, 6.20 mmol) in dimethylformamide (30 ml). The mixture was stirred for mins, quenched with water (50 ml) and extracted with ethyl acetate (2×50 ml). The combined organic extracts were washed with water (4×50 ml) then brine (50 ml). They were dried (MgSO₄) and concentrated to afford an oil which was purified by flash chromatography (20-45% ethyl acetate in hexane) to afford 2.44 g (94%) of a colorless oil: [α]_(D) ²⁰ -35.0° (c 1.41, CH₂ Cl₂); IR (film) 3359, 2981, 2938, 1752, 1740, 1726, 1712, 1512, 1369, 1285, 1177, 1053, 991, 939, 688; ¹ H NMR (CDCl₃) δ 8.15 (2H, m), 7.66 (1H, m), 7.53 (2H, m), 5.90 (2H, m), 5.33 (2H, m), 5.31 (1H, d, J=16.9), 5.18 (1H, d, J=16.9), 4.63 (3H, m), 3.03 (1H, dd, J=17.3, 4.6), 2.74 (1H, dd, J=17.3, 4.9), 1.44 (9H, s). MS (C.I.) 420 (M⁺ +1 20%); 364 (100).

(3S) t-Butyl N-(allyloxycarbonyl)-3-amino-5-hydroxy-4-oxo-pentanoate (81). A mixture of the ester 80 (2.40 g, 5.71 mmol), tetrahydrofuran (200 ml) and 1M aqueous potassium bicarbonate (200 ml) was vigorously stirred at room temperature for 18 h. The layers were separated and the aqueous portion extracted with ethyl acetate (100 ml). The combined organic extracts were washed with brine (100 ml), dried (MgSO₄) and concentrated. The residue was purified by flash chromatography (10-60% ethyl acetate in hexane) to afford 1.48 g (90%) of pale yellow oil: [α]_(D) ²⁰ -5.9° (c 1.06, CH₂ Cl₂); IR (film) 3345, 2981, 2936, 1739, 1725, 1712, 1692, 1515, 1368, 1259, 1158, 1051; ¹ H NMR (CDCl₃) δ 5.92 (2H, m), 5.30 (2H, m), 4.36-4.69 (5H, m), 3.05 (1H, dd, J=17.4, 4.3), 2.93 (1H, t), 2.70 (1H, dd, J=17.4, 4.9), 1.43 (9H, s). Anal. Calcd for C₁₈ H₂₁ N₁ O₆. 0.25H₂ O: C, 53.51; H, 7.43; N, 4.80. Found: C, 53.61; H, 7.18; N, 4.71. MS (C.I.) 280 (M⁺ +1, 87%); 232 (100).

(3S) t-Butyl N-(allyloxycarbonyl)-3-amino-5-(2,6-dichlorophenyl-methoxy)-4-oxo-pentanoate (82). A stirred mixture of alcohol 81 (1.44 g, 5.01 mmol), 2,6-dichlorobenzyl iodide (Abraham et al., J. Chem. Soc., pp. 1605-1607 (1936)) (4.31 g, 15.0 mmol), silver oxide (2.32 g, 10.0 mmol) and dichloromethane (25 ml) was heated under reflux for 45 h. The mixture was allowed to cool to room temperature then diluted with water (50 ml) then extracted with ethyl acetate (50 ml, 25 ml). The organic layer was washed with water (50 ml) then brine (50 ml), dried (MgSO₄), and concentrated. The residue was purifed by flash chromatography (10-100% ethyl acetate in hexane) to afford 1.65 g (74%) of a colorless oil: [α]_(D) ²⁰ +8.8° (c 1.13, CH₂ Cl₂); IR (film) 3339, 2980, 2935, 1724, 1712, 1503, 1438, 1368, 1246, 1156, 1106, 770; ¹ H NMR (CDCl₃) δ 7.33 (2H, m), 7.22 (1H, dd), 5.92 (2H, m), 5.28 (2H, m), 4.87 (2H, m), 4.67 (1H, m), 4.58 (2H, br d), 4.56 (1H, d, J=16.9), 4.31 (1H, d, J=16.9), 3.04 (1H, dd, J=16.7, 4.5), 2.77 (1H, dd, J=16.7, 4.9), 1.40 (9H, s). Anal. Calcd. for C₂₀ H₂₅ Cl₂ N₁ O₆. 0.25H₂ O: C, 53.28; H, 5.70; N, 3.11. Found: C, 53.15; H, 5.52; N, 2.98. M.S. (C.I.); 446 (M⁺, 27%); 390 (100).

(3RS) t-Butyl N-[N-phenylmethyloxycarbonylvalaninyl-alaninyl]-3-amino-5-(2,6-dichlorophenylmethyloxy)-4-oxo-pentanoate (83a). 1-(3-Dimethylamino-propyl)-3-ethylcarbodiimide hydrochloride (379 g, 1.98 mmol) and 1-hydroxybenzotriazole (486 mg, 3.60 mmol) were added to a stirred solution of N-phenyl-methyloxycarbonylvalinyl-alanine (637 mg, 1.98 mmol) in tetrahydrofuran (40 ml) and water (1 ml). The mixture was stirred for 15 mins and then the ether 82 (802 mg, 1.80 mmol) and bis (triphenyl-phosphine)palladium (II) chloride (ca 5 mg) were added. Tributyltin hydride (785 mg, 725 l, 2.70 mmol) was then added dropwise during 20 mins and the resulting solution was stirred for 3.75 h and then quenched with 1M hydrochloric acid (50 ml). The mixture was extracted twice with ethyl acetate. The combined organic extracts were washed with 1M hydrochloric acid, twice with aqueous sodium bicarbonate, water and then brine, dried (MgSO₄) and concentrated. The residue was purified by flash chromatography (10-30% ethyl acetate - dichloromethane) to afford 941 mg (79%) of pale yellow solid: m.p. 148°-52° C.; IR (KBr) 3287, 3070, 1730, 1691, 1641, 1536, 1369, 1289, 1247, 1156; ¹ H NMR (CDCl₃) δ 7.33 (8H, m), 7.23 (1H, dd), 6.61 (1H, br, d), 5.42 (1H, br, d), 5.11 (2H, s), 4.85 (3H, m), 4.50 (1H, m), 4.40 (1H, d, J=16.9), 4.26 (1H, d, J=16.9), 4.02 (1H, m), 2.99 (1H, dd, J=16.8, 4.7), 2.73 (1H, dd, J=16.8, 5.0), 2.09 (1H, m), 1.37 (12H, m), 0.96 (3H, d, J=6.9), 0.91 (3H, d, J=6.8). Anal. Calcd. for C₃₂ H₄₁ Cl₂ N₃ O₈. 0.25H₂ O: C, 57.25; H, 6.23; Cl, 10.57; N, 6.26. Found: C, 57.18; H, 6.23; Cl, 10.58; N, 5.95. M.S. (+FAB); 667 (M⁺ 1, 1%); 666 (3), 159 (25), 91 (100).

(3RS) t-Butyl N-[(N-acetyl-O-t-butyltyrosinyl)-valaninyl-alaninyl]-3-amino-5-(2,6-dichlorophenylmethyloxy)-4-oxo-pentanoate (83b), was prepared by the method described for 83a to afford 554 mg (64%) of colorless solid: m.p. 184°-6° C.; IR (KBr) 3282, 3075, 1736, 1690, 1633, 1536, 1508, 1366, 1236, 1161; ¹ H NMR (d₆ -DMSO) δ 8.49 (1H, d), 8.14 (1H, d), 8.08 (1H, d), 7.84 (1H, d), 7.43 (3H, m), 7.14 (2H, d), 6.83 (2H, d), 4.71 (2H, s), 4.51 (2H, m), 4.36 (2H, dd), 4.17 (2H, m), 2.93 (1H, m), 2.73 (1H, m), 1.94 (1H, m), 1.74 (3H, s), 1.37 (9H, s), 1.23 (12H, m), 0.83 (6H, m). M.S. (+FAB); 793 (M⁺ 1, 4%); 737 (5), 681 (1), 178 (40), 159 (45), 136 (100), 107 (40). M.S. (-FAB); 792 (20), 791 (40), 447 (100).

(RS) N-[N-(Phenylmethyloxy)carbonyl-valinyl-alaninyl]-3-amino-5-(2,6-dichlorophenylmethyloxy)-4-oxo-pentanoic acid (84a; V). Trifluoroacetic acid (5 ml) was added to a stirred solution of the ester 83a, (918 mg, 1.38 mmol) in dichloromethane (20 ml). The mixture was stirred for 2.5 h then evaporated to dryness. The residue was treated with ether (25 ml) and evaporated to dryness. This procedure was repeated three times. The resulting product was triturated with ether (10 ml) and then dried to afford 730 mg (87%) of light brown powder: m.p. 156°-60° C.; IR (KBr) 3282, 2965, 1702, 1694, 1642, 1536, 1438, 1246, 1230; ¹ H NMR (d₆ -DMSO) δ 8.48 (1H, d), 8.09 (1H, d), 7.47 (9H, m), 5.02 (2H, s), 4.70 (2H, s), 4.49 (1H, m), 4.37 (2H, dd), 4.27 (1H, m), 3.88 (1H, m), 2.75 (1H, dd), 2.54 (1H, dd), 1.96 (1H, m), 1.19 (3H, s), 0.84 (6H, m). Anal. Calcd. for C₂₈ H₃₃ Cl₂ N₃ O₈. 0.5H₂ O: C, 54.27; H, 5.53; Cl, 11.45; N, 6.78. Found: C, 54.49; H, 5.39; Cl, 11.33; N, 6.73. M.S. (+FAB); 610 (M⁺ 1, 10%); 91 (100).

(RS) N-[N-(Acetyl)tyrosinyl-valinyl-alaninyl]-3-amino-5-(2,6-dichlorophenylmethyloxy)-4-oxo-pentanoic acid (84b; W), was obtained as a colorless powder (95%) by the method used for 84a. m.p. 165°-8° C.: IR (KBr) 3295, 2968, 1733, 1642, 1517, 1438, 1231, 1105; ¹ H NMR (d₆ -DMSO) 9.2 (1H, br, s), 8.48 (1H, br, d), 8.14 (1H, br, d), 8.02 (1H, br, d), 7.81 (1H, br, d), 7.45 (3H, m), 7.02 (2H, d), 6.62 (2H, d), 4.70 (2H, s), 4.12-4.53 (3H, m), 3.60 (3H, m), 2.51-2.92 (4H, m), 1.96 (1H, m), 1.75 (3H, s), 1.21 (3H, d), 0.83 (6H, m). Anal. Calcd. for C₃₁ H₃₈ Cl₂ N₄ O₉. H₂ O: C, 53.22; H, 5.76; Cl, 10.14; N, 8.09. Found: C, 53.33; H, 5.54; Cl, 10.02; N, 7.85. M.S. (+FAB); 682 (M⁺ 2, 30%); 681 (67), 158 (100). (-FAB); 680 (45), 679 (100).

The data of the examples above demonstrate that compounds according to this invention display inhibitory activity towards IL-1β Converting Enzyme.

Insofar as the compounds of this invention are able to inhibit ICE in vitro and furthermore, may be delivered orally to mammals, they are of evident clinical utility for the treatment of IL-1 mediated diseases. These tests are predictive of the compounds ability to inhibit ICE in vivo.

While we have described a number of embodiments of this invention, it is apparent that our basic constructions may be altered to provide other embodiments which utilize the products and processes of this invention. Therefore, it will be appreciated that the scope of this invention is to be defined by the appended claims, rather than by the specific embodiments which have been presented by way of example. 

We claim:
 1. A compound represented by the formula: ##STR116## wherein: X₁ is CH or N;g is 0 or 1; each J is independently selected from the group consisting of --H, --OH, and --F, provided that when a first and second J are bound to the same C and said first J is --OH, said second J is -H; m is 0, 1, or 2; T is --Ar₃, --OH, --CF₃, --CO--CO₂ H, --CO₂ H, --CO--CH₂ OH, --CO--NHOH, --SO₂ --NHR, --SO₃ H, --PO(OH)NH₂, --CONHCN, --OSO₃ H, --CO--NHSO₂ R₁₆, --PO(OH)₂, --PO(OH)(OR₁₆), --PO(OH)(R₁₆), --OPO(OH)₂, --OPO(OH)(OR₁₆), --OPO(OH)(R₁₆), --NHPO(OH)₂, --NHPO(OH)(OR₁₆), --NHPO(OH)(R₁₆), ##STR117## R₁₅ is --H, a --C₁₋₆ alkyl group, or the bond linking T to (CJ₂)_(m) ; R₁₆ is a --C₁₋₆ alkyl group; R₁ is ##STR118## wherein: any hydrogen bound to any ring carbon is optionally replaced with Q₁ ;any hydrogen bound to any ring nitrogen is optionally replaced by R₅ ; any hydrogen bound to any ring atom is optionally replaced by ═O, --OH, --CO₂ H, or halogen; and any saturated ring is optionally unsaturated at one or two bonds; each X₂ is independently selected from --O--, --CH₂ --, --NH--, --S--, --SO--, or --SO₂ --; each X₅ is independently selected from ##STR119## a is 0 or 1; each d is independently 0, 1, or 2 and a+d+d equals 2; R₃ is --CN, --CH═CH--R₉, --CH═N--O--R₉, --(CH₂)₁₋₃ --T₁ --R₉, --CJ₂ --R₉, --CO--R₁₃, or ##STR120## each R₄ is independently selected from --H, --Ar₁, -R₉, --T₁ --R₉, or --(CH₂)₁,2,3 --T₁ --R₉, each T₁ is independently selected from --CH═CH--, --O--, --S--, --SO--, --SO₂ --, --NR₁₀ --, --NR₁₀ --CO--, --CO--, --O--CO--, --CO--O--, --CO--NR₁₀ --, --O--CO--NR₁₀ --, --NR₁₀ --CO--O--, --NR₁₀ --CO--NR₁₀ --, --SO₂ --NR₁₀ --, --NR₁₀ --SO₂ --, or --NR₁₀ --SO₂ --NR₁₀ --, each R₅ is independently selected from --H, --Ar₁, --CO--Ar₁, --SO₂ --Ar₁, -R₉, --CO--R₉, --CO--O--R₉, --SO₂ --R₉, ##STR121## R_(5') is selected from --Ar₁, --SO₂ --Ar₁, --CO--R_(9a), --SO₂ --R₉, ##STR122## each R₉ and R_(9a) is a C₁₋₆ straight or branched alkyl group, wherein:any hydrogen atom in any of said alkyl groups is optionally replaced by --OH, --F, or ═O; and 1to 2 hydrogen atoms are optionally substituted with Ar₁ ; each R₁₀ is independently selected from --H or C₁₋₆ straight or branched alkyl; each R₁₃ is independently selected from --Ar₂ and -R₄ ; each Ar₁ is independently selected from:an aryl group containing 1 to 3 rings and a total of 6, 10, 12, or 14 carbon atoms; a cycloalkyl group containing 1 to 3 rings and a total of 3 to 15 carbon atoms, wherein said cycloalkyl group is optionally benzofused; and a heterocycle group containing 1 to 3 rings and a total of 5 to 15 ring atoms, wherein said heterocycle group contains at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, and optionally contains one or more double bonds; wherein any hydrogen bound to any ring atom in any Ar₁ is optionally replaced by ═O, --OH, perfluoro C₁₋₃ alkyl, or -Q₁ ; each Ar₂ is independently selected from: ##STR123## wherein any ring is optionally substituted by -Q₁ ; each X is independently selected from ═N-- or ═CH--; each Y is independently selected from --O-- or --S--; Ar₃ is a phenyl ring; a 5-membered heteroaromatic ring; or a 6-membered heteroaromatic ring; wherein any of said heteroaromatic rings comprises 1 to 3 heteroatom groups selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, and wherein any hydrogen atom bound to any ring atom in Ar₃ is optionally replaced by ═O, --OH, halogen, perfluoro C₁₋₃ alkyl, or --CO₂ H; each Q₁ is independently selected from --Ar₁, -R₉, -T₁ -R₉, or --(CH₂)₁,2,3 -T₁ -R₉, provided that when --Ar₁ is substituted with a Q₁ group which comprises one or more additional --Ar₁ groups, said additional --Ar₁ groups are not substituted with Q₁.
 2. The compound according to claim 1, wherein R_(5') is --CO--R_(9a).
 3. The compound according to claim 2, wherein R_(9a) is a C₁₋₆ straight or branched alkyl group, wherein each hydrogen in said alkyl group is optionally replaced by --OH, --F, or ═O; and up to two hydrogen atoms in said alkyl group are optionally replaced by Ar₁.
 4. The compound according to claim 2, wherein R_(9a) is a C₂ straight alkyl group, wherein each hydrogen in said alkyl group is optionally replaced by --OH, --F, or ═O; and up to two hydrogen atoms in said alkyl group are optionally replaced by Ar₁.
 5. The compound according to claim 4, wherein R₁ is: ##STR124## and each Ar₁ is independently selected from:an aryl group containing 1 to 3 rings and a total of 6, 10, 12, or 14 carbon atoms; a cycloalkyl group containing 1 to 3 rings and a total of 3 to 15 carbon atoms, wherein said cycloalkyl group is optionally benzofused; and a heterocycle group containing 1 to 3 rings and a total of 5 to 15 ring atoms, wherein said heterocycle group contains at least one heteroatom group selected from --O--, --S--, --SO--, --SO₂ --, ═N--, and --NH--, and optionally contains one or more double bonds; wherein any hydrogen bound to any ring atom in any Ar₁ is optionally replaced by ═O, --OH, perfluoro C₁₋₃ alkyl, or -Q₁.
 6. The compound according to claim 5, selected from: ##STR125##
 7. A pharmaceutical composition for treating or preventing an autoimmune disease comprising a pharmaceutically effective amount of an ICE inhibitor according to any one of claims 1-6 and a pharmaceutically acceptable carrier.
 8. A pharmaceutical composition for treating or preventing an inflammatory disease comprising a pharmaceutically effective amount of an ICE inhibitor according to any one of claims 1-2 and a pharmaceutically acceptable carrier.
 9. A pharmaceutical composition for treating or preventing a neurodegenerative disease comprising a pharmaceutically effective amount of an ICE inhibitor according to any one of claims 1-2 and a pharmaceutically acceptable carrier.
 10. A pharmaceutical composition for inhibiting an ICE-mediated function comprising a pharmaceutically effective amount of an ICE inhibitor according to any one of claims 1-2 and a pharmaceutically acceptable carrier.
 11. A method for treating or preventing a disease selected from the group consisting of IL-1 mediated disease, autoimmune disease, inflammatory disease and neurodegenerative disease in a patient comprising the step of administering to said patient a pharmaceutical composition according to any one of claims 6 to
 10. 12. A pharmaceutical composition for treating or preventing an IL-1 mediated disease comprising a pharmaceutically effective amount of an ICE inhibitor according to any one of claims 1-6 and a pharmaceutically acceptable carrier. 